Method and apparatus for NR V2X sidelink HARQ procedure

ABSTRACT

Apparatuses and methods for obtaining and providing hybrid automatic repeat request acknowledgement (HARQ-ACK) information. A method for providing HARQ-ACK information includes receiving a configuration for a slot offset value and receiving a physical sidelink shared channel (PSSCH) over a number of sub-channels in a first slot. The PSSCH includes a transport block (TB). The method includes determining a second slot as an earliest slot with resources for transmission of a physical sidelink feedback channel (PSFCH) that is after the first slot by a number of slots equal to the slot offset value. The PSFCH includes the HARQ-ACK information that is in response to reception of the TB. The method further includes transmitting the PSFCH in the second slot.

CROSS-REFERENCE TO RELATED APPLICATIONS AND CLAIM OF PRIORITY

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/838,042 filed Apr. 24, 2019, U.S. Provisional Patent ApplicationNo. 62/842,075 filed May 2, 2019, U.S. Provisional Patent ApplicationNo. 62/854,594 filed May 30, 2019, U.S. Provisional Patent ApplicationNo. 62/854,618 filed May 30, 2019, U.S. Provisional Patent ApplicationNo. 62/866,698 filed Jun. 26, 2019, and U.S. Provisional PatentApplication No. 62/901,320 filed Sep. 17, 2019, the disclosures of whichare incorporated herein by reference in their entireties.

TECHNICAL FIELD

The present disclosure relates to vehicle to everything (V2X) sidelinkhybrid automatic repeat request (HARQ) procedures.

BACKGROUND

5G New Radio Interface/Access (NR) systems support multiple servicesincluding enhanced mobile broadband (eMBB), massive machine typecommunication (mMTC), ultra-reliable low latency communication (uRLLC),and V2X. These services have enhanced features including higher datarates, higher operating frequency bands, wider bandwidths, greaterreliability, shorter latency, and increased number of connectivitiesthan previous services. V2X includes Vehicle-to-Vehicle (V2V)Communications, Vehicle-to-Infrastructure (V2I) Communications, andVehicle-to-Pedestrian (V2P) Communications. These three types of V2X canuse “co-operative awareness” to provide more intelligent services forend-users. Because the use of V2X is increasing, sidelink HARQprocedures need to improve to keep up with the demand.

SUMMARY

The present disclosure relates to monitoring downlink control channelsfor communication with multiple transmission reception points.

In one embodiment, a method for a user equipment (UE) to provideHARQ-acknowledgement (ACK) information is provided. The method includesreceiving a configuration for a slot offset value and receiving aphysical sidelink shared channel (PSSCH) over a number of sub-channelsin a first slot. The PSSCH includes a transport block (TB). The methodincludes determining a second slot as an earliest slot with resourcesfor transmission of a physical sidelink feedback channel (PSFCH) that isafter the first slot by a number of slots equal to the slot offsetvalue. The PSFCH includes the HARQ-ACK information that is in responseto reception of the TB. The method further includes transmitting thePSFCH in the second slot.

In another embodiment, a UE is provided. The UE includes a transceiverconfigured to receive a configuration for a slot offset value andreceive a PSSCH over a number of sub-channels in a first slot. The PSSCHincludes a TB. The UE also includes a processor operably connected tothe transceiver. The processor is configured to determine a second slotas an earliest slot with resources for transmission of a PSFCH that isafter the first slot by a number of slots equal to the slot offsetvalue. The PSFCH includes HARQ-ACK information in response to receptionof the TB. The transceiver is further configured to transmit the PSFCHin the second slot.

In yet another embodiment, a method for a UE to obtain HARQ-ACKinformation is provided. The method includes transmitting aconfiguration for a slot offset value and transmitting a PSSCH over anumber of sub-channels in a first slot. The PSSCH includes a TB. Themethod includes determining a second slot as an earliest slot withresources for reception of a PSFCH that is after the first slot by anumber of slots equal to the slot offset value and receiving the PSFCHin the second slot. The PSFCH includes the HARQ-ACK information that isin response to transmission of the TB.

In yet another embodiment, a UE is provided. The UE includes atransceiver configured to transmit a configuration for a slot offsetvalue and transmit a PSSCH over a number of sub-channels in a firstslot. The PSSCH includes a TB. The UE also includes a processor operablyconnected to the transceiver. The processor is configured to determine asecond slot as an earliest slot with resources for reception of a PSFCHthat is after the first slot by a number of slots equal to the slotoffset value. The transceiver is further configured to receive the PSFCHin the second slot. The PSFCH includes HARQ-ACK information in responseto transmission of the TB.

Other technical features may be readily apparent to one skilled in theart from the following figures, descriptions, and claims.

Before undertaking the DETAILED DESCRIPTION below, it can beadvantageous to set forth definitions of certain words and phrases usedthroughout this disclosure. The term “couple” and its derivatives referto any direct or indirect communication between two or more elements,whether or not those elements are in physical contact with one another.The terms “transmit,” “receive,” and “communicate,” as well asderivatives thereof, encompass both direct and indirect communication.The terms “include” and “comprise,” as well as derivatives thereof, meaninclusion without limitation. The term “or” is inclusive, meaningand/or. The phrase “associated with,” as well as derivatives thereof,means to include, be included within, interconnect with, contain, becontained within, connect to or with, couple to or with, be communicablewith, cooperate with, interleave, juxtapose, be proximate to, be boundto or with, have, have a property of, have a relationship to or with, orthe like. The term “controller” means any device, system or part thereofthat controls at least one operation. Such a controller can beimplemented in hardware or a combination of hardware and software and/orfirmware. The functionality associated with any particular controllercan be centralized or distributed, whether locally or remotely. Thephrase “at least one of,” when used with a list of items, means thatdifferent combinations of one or more of the listed items can be used,and only one item in the list can be needed. For example, “at least oneof: A, B, and C” includes any of the following combinations: A, B, C, Aand B, A and C, B and C, and A and B and C.

Moreover, various functions described below can be implemented orsupported by one or more computer programs, each of which is formed fromcomputer readable program code and embodied in a computer readablemedium. The terms “application” and “program” refer to one or morecomputer programs, software components, sets of instructions,procedures, functions, objects, classes, instances, related data, or aportion thereof adapted for implementation in a suitable computerreadable program code. The phrase “computer readable program code”includes any type of computer code, including source code, object code,and executable code. The phrase “computer readable medium” includes anytype of medium capable of being accessed by a computer, such as readonly memory (ROM), random access memory (RAM), a hard disk drive, acompact disc (CD), a digital video disc (DVD), or any other type ofmemory. A “non-transitory” computer readable medium excludes wired,wireless, optical, or other communication links that transporttransitory electrical or other signals. A non-transitory computerreadable medium includes media where data can be permanently stored andmedia where data can be stored and later overwritten, such as arewritable optical disc or an erasable memory device.

Definitions for other certain words and phrases are provided throughoutthis disclosure. Those of ordinary skill in the art should understandthat in many, if not most, instances, such definitions apply to prior aswell as future uses of such defined words and phrases.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and itsadvantages, reference is now made to the following description taken inconjunction with the accompanying drawings, in which like referencenumerals represent like parts:

FIG. 1 illustrates an example wireless network according to variousembodiments of the present disclosure;

FIG. 2 illustrates an example user equipment according to variousembodiments of the present disclosure;

FIG. 3 illustrates an example base station (BS) according to variousembodiments of the present disclosure;

FIG. 4A illustrates an example transmitter structure according tovarious embodiments of the present disclosure;

FIG. 4B illustrates an example receiver structure according to variousembodiments of the present disclosure;

FIG. 4C illustrates an example for a mapping of a channel stateinformation reference signal (CSI-RS) port to antenna elements accordingto various embodiments of the present disclosure

FIG. 5 illustrates an example sidelink (SL) interface according tovarious embodiments of the present disclosure;

FIG. 6 illustrates a first example of codebook group (CBG)-basedHARQ-ACK information reporting on sidelink according to variousembodiments of the present disclosure

FIG. 7 illustrates an example resource pool according to variousembodiments of the present disclosure;

FIG. 8 illustrates a second example of CBG-based HARQ-ACK informationreporting on sidelink according to various embodiments of the presentdisclosure;

FIG. 9 illustrates random selection by UEs of a PSFCH resource accordingto various embodiments of the present disclosure;

FIG. 10 illustrates selection, by UEs, of PSFCH resources according topredefined rules according to various embodiments of the presentdisclosure;

FIG. 11 illustrates assignments of UEs to PSFCH resources according tovarious embodiments of the present disclosure;

FIG. 12 illustrates random selection by UEs of a resource for a PSFCHtransmission according to a HARQ-ACK information value according tovarious embodiments of the present disclosure;

FIG. 13 illustrates assignments of UEs to PSFCH resources according tovarious embodiments of the present disclosure;

FIG. 14 illustrates a field in a SCI format provided in a PSCCHreception indicating presence or absence of position information in aPSSCH reception scheduled by the SCI format according to variousembodiments of the present disclosure;

FIG. 15 illustrates a mapping between PSCCH/PSSCH resources and PSFCHresources according to various embodiments of the present disclosure;

FIG. 16 illustrates a mapping of PSCCH/PSSCH resources to PSFCHresources according to various embodiments of the present disclosure;

FIG. 17 illustrates a mapping of PSCCH/PSSCH resources with associatedPSFCH resources in different slots according to various embodiments ofthe present disclosure;

FIG. 18 illustrates a mapping between a PSCCH/PSSCH subchannel in a slotand a PSFCH resource according to various embodiments of the presentdisclosure;

FIG. 19 illustrates a mapping for a PSCCH/PSSCH subchannel in a slot toPSFCH resources according to various embodiments of the presentdisclosure;

FIG. 20 illustrates UEs marked in various geographical zones accordingto various embodiments of the present disclosure;

FIG. 21 illustrates an association between a PSCCH/PSSCH reception at asubchannel in a slot and a corresponding PSFCH resource according tovarious embodiments of the present disclosure;

FIG. 22 illustrates an association of PSFCH resources reserved by areservation signal with a PSCCH/PSSCH reception in a subchannel in aslot according to various embodiments of the present disclosure;

FIG. 23 illustrates a determination for a PSFCH recourse in response tomultiple PSCCH/PSSCH receptions according to various embodiments of thepresent disclosure;

FIG. 24 illustrates an indication of a second slot for a PSFCHtransmission in response to a PSCCH/PSSCH reception at a subchannel in afirst slot according to various embodiments of the present disclosure;

FIG. 25 illustrates an indication by a reservation signal of a secondslot for PSFCH transmission in response to a PSCCH/PSSCH reception at asubchannel in a first slot according to various embodiments of thepresent disclosure;

FIG. 26 illustrates a sidelink power saving signal or channel accordingto various embodiments of the present disclosure;

FIG. 27 illustrates a Mode 1 power saving signal or channel for a PDCCHaccording to various embodiments of the present disclosure;

FIG. 28 illustrates a method for indicating to a UE whether or not tomonitor PDCCH or PSSCH in next respective DRX cycles on the Uu link orthe sidelink through a DCI format in a PDCCH power saving signal orchannel in Mode 1 sidelink according to various embodiments of thepresent disclosure;

FIG. 29 illustrates a method of a Mode 1 power saving signal or channelfor PSCCH and PDCCH according to various embodiments of the presentdisclosure;

FIG. 30 illustrates a use of separate Mode 1 power savings channels forsidelink and Uu link according to various embodiments of the presentdisclosure;

FIG. 31 illustrates an RRC configuration for power saving signals orchannels according to various embodiments of the present disclosure;

FIG. 32 illustrates an RRC and PC5-RRC configuration for a power savingsignal or channel according various embodiments of the presentdisclosure;

FIG. 33 illustrates a sidelink power saving signal or channel in a formof a reservation signal according to various embodiments of the presentdisclosure;

FIG. 34 illustrates partial resource sensing and resource selection orreselection according to various embodiments of the present disclosure;

FIG. 35 illustrates partial resource sensing and resource selection orreselection with a power saving signal or channel according to variousembodiments of the present disclosure;

FIG. 36 illustrates a method of providing HARQ-ACK information accordingto various embodiments of the present disclosure; and

FIG. 37 illustrates a method of obtaining HARQ-ACK information accordingto various embodiments of the present disclosure.

DETAILED DESCRIPTION

FIGS. 1 through 37, discussed below, and the various embodiments used todescribe the principles of the present disclosure in this disclosure areby way of illustration only and should not be construed in any way tolimit the scope of the disclosure. Those skilled in the art willunderstand that the principles of the present disclosure can beimplemented in any suitably arranged wireless communication system.

To meet the demand for wireless data traffic having increased sincedeployment of 4G communication systems, efforts have been made todevelop an improved 5G or pre-5G communication system. Therefore, the 5Gor pre-5G communication system is also called a ‘Beyond 4G Network’ or a‘Post LTE System’.

A 5G communication system can be implemented in higher frequency(mmWave) bands, such as 28 GHz or 60 GHz bands or, in general, above 6GHz bands, so as to accomplish higher data rates, or in lower frequencybands, such as below 6 GHz, to enable robust coverage and mobilitysupport. To decrease propagation loss of the radio waves and increasethe transmission distance, the beamforming, massive multiple-inputmultiple-output (MIMO), Full Dimensional MIMO (FD-MIMO), array antenna,an analog beam forming, large scale antenna techniques are considered in5G communication systems. In addition, in 5G communication systems,development for system network improvement is under way based onadvanced small cells, cloud Radio Access Networks (RANs), ultra-densenetworks, device-to-device (D2D) communication, wireless backhaul,moving network, cooperative communication, Coordinated Multi-Points(CoMP), reception-end interference cancellation and the like.

The discussion of 5G systems and frequency bands associated therewith isfor reference as certain embodiments of the present disclosure can beimplemented in 5G systems. However, the present disclosure is notlimited to 5G systems or the frequency bands associated therewith, andembodiments of the present disclosure can be utilized in connection withany frequency band.

FIG. 1 illustrates an example wireless network 100 according to variousembodiments of the present disclosure. The embodiment of the wirelessnetwork 100 shown in FIG. 1 is for illustration only. Other embodimentsof the wireless network 100 can be used without departing from the scopeof the present disclosure.

The wireless network 100 includes a BS 101, a BS 102, and a BS 103. TheBS 101 communicates with the BS 102 and the BS 103. The BS 101 alsocommunicates with at least one Internet Protocol (IP) network 130, suchas the Internet, a proprietary IP network, or other data network.Instead of “BS”, an option term such as “eNB” (enhanced Node B) or “gNB”(general Node B) can also be used. Depending on the network type, theterm ‘base station’ can refer to any component (or collection ofcomponents) configured to provide wireless access to a network, such astransmit point (TP), transmit-receive point (TRP), a gNB, a macrocell, afemtocell, a WiFi access point (AP), or other wirelessly enableddevices. Base stations can provide wireless access in accordance withone or more wireless communication protocols, e.g., 5G 3GPP New RadioInterface/Access (NR), long term evolution (LTE), LTE advanced (LTE-A),High Speed Packet Access (HSPA), Wi-Fi 802.11a/b/g/n/ac, etc. The terms‘gNB’ and ‘TRP’ can be used interchangeably in this disclosure to referto network infrastructure components that provide wireless access toremote terminals. Also, depending on the network type, the term UE canrefer to any component such as mobile station, subscriber station,remote terminal, wireless terminal, receive point, or user device. A UEcan be a mobile device or a stationary device.

The gNB 102 provides wireless broadband access to the network 130 for afirst plurality of UEs within a coverage area 120 of the gNB 102. Thefirst plurality of UEs includes a UE 111, which can be located in asmall business; a UE 112, which can be located in an enterprise (E); aUE 113, which can be located in a WiFi hotspot (HS); a UE 114, which canbe located in a first residence (R); a UE 115, which can be located in asecond residence (R); and a UE 116, which can be a mobile device (M)like a cell phone, a wireless laptop, a wireless PDA, or the like. ThegNB 103 provides wireless broadband access to the network 130 for asecond plurality of UEs within a coverage area 125 of the gNB 103. Thesecond plurality of UEs includes the UE 115 and the UE 116. In someembodiments, one or more of the gNBs 101-103 can communicate with eachother and with the UEs 111-116 using 5G, LTE, LTE-A, WiMAX, or otheradvanced wireless communication techniques.

In various embodiments, UE 116 can communicate directly with another UE118 such that UE 116 can act as a gNB for UE 118 as discussed in greaterdetail below. For example, in some embodiments, the UE 116 and/or UE 118may be a vehicle and may conduct V2X communications as discussed ingreater detail below.

Dotted lines show the approximate extents of the coverage areas 120 and125, which are shown as approximately circular for the purposes ofillustration and explanation only. For example, the coverage areasassociated with gNBs, such as the coverage areas 120 and 125, can haveother shapes, including irregular shapes, depending upon theconfiguration of the gNBs and variations in the radio environmentassociated with natural and man-made obstructions.

Although FIG. 1 illustrates one example of a wireless network 100,various changes can be made to FIG. 1. For example, the wireless network100 can include any number of gNBs and any number of UEs in any suitablearrangement. The gNB 101 can communicate directly with any number of UEsand provide those UEs with wireless broadband access to the network 130.Similarly, each gNB 102-103 can communicate directly with the network130 and provide UEs with direct wireless broadband access to the network130. Further, the gNB 101, 102, and/or 103 can provide access to otheror additional external networks, such as other types of data networks.

FIG. 2 illustrates an example UE 116 according to the presentdisclosure. The embodiment of the UE 116 illustrated in FIG. 2 is forillustration only, and the UEs 111-118 of FIG. 1 can have the same orsimilar configuration. However, UEs come in a wide variety ofconfigurations, and FIG. 2 does not limit the scope of the presentdisclosure to any particular implementation of a UE.

The UE 116 includes one or more transceivers 210, a microphone 220, aspeaker 230, a processor 240, an input/output (I/O) interface 245, aninput 250, a display 255, and a memory 260. The memory 260 includes anoperating system (OS) program 261 and one or more applications 262.

The transceiver 210 includes transmit (TX) processing circuitry 215 tomodulate signals, receive (RX) processing circuitry 225 to demodulatesignals, and an antenna array 205 including antennas to send and receivesignals. The antenna array 205 receives an incoming signal transmittedby a gNB of the wireless network 100 of FIG. 1. The transceiver 210down-converts the incoming RF signal to generate an intermediatefrequency (IF) or baseband signal. The IF or baseband signal is sent tothe RX processing circuitry 225, which generates a processed basebandsignal by filtering, decoding, and/or digitizing the baseband or IFsignal. The RX processing circuitry 225 transmits the processed basebandsignal to the speaker 230 (such as for voice data) or to the processor240 for further processing (such as for web browsing data).

The TX processing circuitry 215 receives analog or digital voice datafrom the microphone 220 or other outgoing baseband data (such as webdata, e-mail, or interactive video game data) from the processor 240.The TX processing circuitry 215 encodes, multiplexes, and/or digitizesthe outgoing baseband data to generate a processed baseband or IFsignal. The RF transceiver 210 receives the outgoing processed basebandor IF signal from the TX processing circuitry 215 and up-converts thebaseband or IF signal to an RF signal that is transmitted via theantenna array 205.

The processor 240 can include one or more processors or other processingdevices and execute the OS program 261 stored in the memory 260 in orderto control the overall operation of the UE 116. For example, theprocessor 240 can control the reception of forward channel signals andthe transmission of reverse channel signals by the RF transceiver 210,the RX processing circuitry 225, and the TX processing circuitry 215 inaccordance with well-known principles. In some embodiments, theprocessor 240 includes at least one microprocessor or microcontroller.

The processor 240 can execute other processes and programs resident inthe memory 260, such as operations for non-zero power or zero powerchannel state information reference signal (CSI-RS) reception andmeasurement for systems. The processor 240 can move data into or out ofthe memory 260 as part of an executing process. In some embodiments, theprocessor 240 is configured to execute the applications 262 based on theOS program 261 or in response to signals received from gNBs or anoperator. The processor 240 is also coupled to the I/O interface 245,which provides the UE 116 with the ability to connect to other devicessuch as laptop computers and handheld computers. The I/O interface 245is the communication path between these accessories and the processor240.

The processor 240 is also coupled to the input 250 (e.g., keypad,touchscreen, button etc.) and the display 255. The operator of the UE116 can use the input 250 to enter data into the UE 116. The display 255can be a liquid crystal display or other display capable of renderingtext and/or at least limited graphics, such as from web sites.

The memory 260 is coupled to the processor 240. The memory 260 caninclude at least one of a random-access memory (RAM), Flash memory, orother read-only memory (ROM).

Although FIG. 2 illustrates one example of UE 116, various changes canbe made to FIG. 2. For example, various components in FIG. 2 can becombined, further subdivided, or omitted and additional components canbe added according to particular needs. As a particular example, theprocessor 240 can be divided into multiple processors, such as one ormore central processing units (CPUs) and one or more graphics processingunits (GPUs). Although FIG. 2 illustrates the UE 116 as a mobiletelephone or smartphone, UEs can be configured to operate as other typesof mobile or stationary devices.

FIG. 3 illustrates an example gNB 102 according to the presentdisclosure. The embodiment of the gNB 102 shown in FIG. 3 is forillustration only, and other gNBs of FIG. 1 can have the same or similarconfiguration. However, gNBs come in a wide variety of configurations,and FIG. 3 does not limit the scope of the present disclosure to anyparticular implementation of a gNB. The gNB 101 and the gNB 103 caninclude the same or similar structure as the gNB 102.

As shown in FIG. 3, the gNB 102 includes multiple antennas 370 a-370 n,multiple RF transceivers 372 a-372 n, transmit (TX) processing circuitry374, and receive (RX) processing circuitry 376. In certain embodiments,one or more of the multiple antennas 370 a-370 n include 2D antennaarrays. The gNB 102 also includes a controller/processor 378, a memory380, and a backhaul or network interface 382.

The RF transceivers 372 a-372 n receive, from the antennas 370 a-370 n,incoming RF signals, such as signals transmitted by UEs or other gNBs.The RF transceivers 372 a-372 n down-convert the incoming RF signals togenerate IF or baseband signals. The IF or baseband signals are sent tothe RX processing circuitry 376, which generates processed basebandsignals by filtering, decoding, and/or digitizing the baseband or IFsignals. The RX processing circuitry 376 transmits the processedbaseband signals to the controller/processor 378 for further processing.

The TX processing circuitry 374 receives analog or digital data (such asvoice data, web data, e-mail, or interactive video game data) from thecontroller/processor 378. The TX processing circuitry 374 encodes,multiplexes, and/or digitizes the outgoing baseband data to generateprocessed baseband or IF signals. The RF transceivers 372 a-372 nreceive the outgoing processed baseband or IF signals from the TXprocessing circuitry 374 and up-converts the baseband or IF signals toRF signals that are transmitted via the antennas 370 a-370 n.

The controller/processor 378 can include one or more processors or otherprocessing devices that control the overall operation of the gNB 102.For example, the controller/processor 378 can control the reception offorward channel signals and the transmission of reverse channel signalsby the RF transceivers 372 a-372 n, the RX processing circuitry 376, andthe TX processing circuitry 374 in accordance with well-knownprinciples. The controller/processor 378 can support additionalfunctions as well, such as more advanced wireless communicationfunctions. In some embodiments, the controller/processor 378 includes atleast one microprocessor or microcontroller.

The controller/processor 378 can execute programs and other processesresident in the memory 380, such as an OS. The controller/processor 378can support channel quality measurement and reporting for systems having2D antenna arrays. In some embodiments, the controller/processor 378supports communications between entities, such as web RTC. Thecontroller/processor 378 can move data into or out of the memory 380 aspart of an executing process.

The controller/processor 378 is also coupled to the backhaul or networkinterface 382. The backhaul or network interface 382 allows the gNB 102to communicate with other devices or systems over a backhaul connectionor over a network. The backhaul or network interface 382 can supportcommunications over any suitable wired or wireless connection(s). Forexample, when the gNB 102 is implemented as part of a cellularcommunication system (such as one supporting 5G or new radio accesstechnology or NR, LTE, or LTE-A), the backhaul or network interface 382can allow the gNB 102 to communicate with other gNBs over a wired orwireless backhaul connection. When the gNB 102 is implemented as anaccess point, the backhaul or network interface 382 can allow the gNB102 to communicate over a wired or wireless local area network or over awired or wireless connection to a larger network (such as the Internet).The backhaul or network interface 382 includes any suitable structuresupporting communications over a wired or wireless connection, such asan Ethernet or RF transceiver.

The memory 380 is coupled to the controller/processor 378. The memory380 can include at least one of a RAM, a Flash memory, or other ROM. Incertain embodiments, a plurality of instructions is stored in memory.

Although FIG. 3 illustrates one example of a gNB 102, various changescan be made to FIG. 3. For example, the gNB 102 can include any numberof each component shown in FIG. 3. As a particular example, an accesspoint can include a number of backhaul or network interfaces 382, andthe controller/processor 378 can support routing functions to route databetween different network addresses. As another example, while shown asincluding a single instance of TX processing circuitry 374 and a singleinstance of RX processing circuitry 376, the gNB 102 can includemultiple instances of each (such as one per RF transceiver).

The present disclosure relates generally to wireless communicationsystems and, more specifically, to vehicular communication networkprotocols, including vehicle-to-device, vehicle-to-vehicle, andvehicle-to-network communication resource allocation and synchronizationmethods. A communication system includes a downlink (DL) that conveyssignals from transmission points such as base stations (BSs or gNBs) touser equipments (UEs) and an uplink (UL) that conveys signals from UEsto reception points such as gNBs. Additionally, a communication systemcan include a sidelink (SL) to support transmissions and receptionsamong UEs or among other non-infrastructure-based nodes.

A time unit for DL signaling or for UL signaling on a cell is referredto as a slot and can include one or more symbols. A symbol can alsoserve as an additional time unit. A frequency (or bandwidth (BW)) unitis referred to as a resource block (RB). One RB includes a number ofsub-carriers (SCs). For example, a slot can have duration of 1millisecond or 0.5 milliseconds and include 14 symbols, and an RB canhave a BW of 180 kHz or 360 kHz and include 12 SCs with inter-SC spacingof 15 kHz or 30 kHz.

DL signals include data signals conveying information content, controlsignals conveying DL control information (DCI), and reference signals(RS) that are also known as pilot signals. A gNB can transmit datainformation or DCI through respective physical DL shared channels(PDSCHs) or physical DL control channels (PDCCHs). A gNB can transmitone or more of multiple types of RS including channel state informationRS (CSI-RS) and demodulation RS (DMRS). A CSI-RS is intended for UEs tomeasure channel state information (CSI) or to perform other measurementssuch as ones related to mobility support. A DMRS can be transmitted onlyin the BW of a respective PDCCH or PDSCH and a UE can use the DMRS todemodulate data or control information.

UL signals also include data signals conveying information content,control signals conveying UL control information (UCI), and RS. A UEtransmits data information or UCI through a respective physical ULshared channel (PUSCH) or a physical UL control channel (PUCCH). When aUE simultaneously transmits data information and UCI, the UE canmultiplex both in a PUSCH or transmit them separately in respectivePUSCH and PUCCH. UCI includes hybrid automatic repeat requestacknowledgement (HARQ-ACK) information, indicating correct or incorrectdetection of data transport blocks (TBs) by a UE, scheduling request(SR) indicating whether a UE has data in the UE's buffer, and CSIreports enabling a gNB to select appropriate parameters to perform linkadaptation for PDSCH or PDCCH transmissions to a UE.

A CSI report from a UE can include a channel quality indicator (CQI)informing a gNB of a modulation and coding scheme (MCS) for the UE todetect a data TB with a predetermined block error rate (BLER), such as a10% BLER, of a precoding matrix indicator (PMI) informing a gNB how toprecode signaling to a UE, and of a rank indicator (RI) indicating atransmission rank for a PDSCH. UL RS includes DMRS and sounding RS(SRS). DMRS is transmitted in a BW of a respective PUSCH or PUCCHtransmission. A gNB can use a DMRS to demodulate information in arespective PUSCH or PUCCH. SRS is transmitted by a UE to provide a gNBwith UL CSI and, for a TDD or a flexible duplex system, to also providea PMI for DL transmissions. An UL DMRS or SRS transmission can be based,for example, on a transmission of a Zadoff-Chu (ZC) sequence or, ingeneral, of a CAZAC sequence.

FIG. 4A illustrates an example transmitter structure 401 using OFDMaccording to embodiments of the present disclosure. An embodiment of thetransmitter structure 401 shown in FIG. 4A is for illustration only. Oneor more of the components illustrated in FIG. 4A can be implemented inspecialized circuitry configured to perform the noted functions or oneor more of the components can be implemented by one or more processorsexecuting instructions to perform the noted functions. Other embodimentsare used without departing from the scope of the present disclosure.

Information bits, such as DCI bits or data bits 402, are encoded byencoder 404, rate matched to assigned time/frequency resources by ratematcher 406 and modulated by modulator 408. Subsequently, modulatedencoded symbols and DMRS or CSI-RS 410 are mapped to SCs 412 by SCmapping unit 414, an inverse fast Fourier transform (IFFT) is performedby filter 416, a cyclic prefix (CP) is added by a CP insertion unit(CIU) 418, and a resulting signal 422 is filtered by a filter andtransmitted by an radio frequency (RF) unit 420.

FIG. 4B illustrates an example receiver structure 431 using OFDMaccording to embodiments of the present disclosure. An embodiment of thereceiver structure 431 shown in FIG. 4B is for illustration only. One ormore of the components illustrated in FIG. 4B can be implemented inspecialized circuitry configured to perform the noted functions or oneor more of the components can be implemented by one or more processorsexecuting instructions to perform the noted functions. Other embodimentsare used without departing from the scope of the present disclosure.

A received signal 432 is filtered by filter 434, a CP removal unit 436removes a CP, a filter 438 applies a fast Fourier transform (FFT), SCsde-mapping unit 440 de-maps SCs selected by BW selector unit 442,received symbols are demodulated by a channel estimator and ademodulator unit 444, a rate de-matcher 446 restores a rate matching,and a decoder 448 decodes the resulting bits to provide information bits450.

FIG. 4C illustrates an example for a mapping of a CSI-RS port to antennaelements according to various embodiments of the present disclosure. Invarious embodiments, the transmitter structure 401 and receiverstructure 431 can be implemented as the antenna elements in FIG. 4C. Invarious embodiments, the transmitter structure 401 and receiverstructure 431 can be implemented in FIGS. 2 and 3.

One CSI-RS port is mapped onto a number of antenna elements that can besubstantially larger than one and can be controlled by a bank of analogphase shifters 461. One CSI-RS port can then correspond to one sub-arraythat produces a narrow analog beam through analog beamforming 463. Theanalog beam can be configured to sweep across a wider range of angles467 by varying the phase shifter bank across symbols or slots. A numberof sub-arrays (equal to the number of RF chains) is same as a number ofCSI-RS antenna ports N_(CSI-PORT). A digital beamforming unit 465performs a linear combination across N_(CSI-PORT) analog beams toincrease precoding gain. While analog beams are wideband (hence notfrequency-selective), digital precoding can be varied across frequencysub-bands or resource blocks. For mmWave bands, although a number ofantenna elements can be larger for a given form factor, a number ofCSI-RS antenna ports, that can correspond to the number of digitallyprecoded antenna ports, it typically limited due to hardwareconstraints, such as a feasibility to install a large number ofADCs/DACs at mmWave frequencies.

Traditionally, cellular communication networks have been designed toestablish wireless communication links between UEs and fixedcommunication infrastructure components, such as gNBs, that serve UEs ina wide or local geographic range. However, a wireless network can alsobe implemented by utilizing only device-to-device (D2D) communicationlinks without the need for fixed infrastructure components. This type ofnetwork is typically referred to as an “ad-hoc” network. A hybridcommunication network can support devices that connect both to fixedinfrastructure components and to other D2D-enabled devices. While UEssuch as smartphones can be envisioned for D2D networks, vehicularcommunication can also be supported by a communication protocol wherevehicles exchange control or data information with other vehicles, orwith infrastructure, or with other UEs. Such a network is referred to asa V2X network. Multiple types of communication links can be supported bynodes in a V2X network. The communication links can utilize same ordifferent protocols and systems.

Direct communication between vehicles in V2V is based on a sidelink (SL)interface. Sidelink is the UE to UE interface for SL communication andSL discovery. The SL corresponds to the PC5 interface. SL communicationis defined as a functionality enabling proximity services (ProSe) DirectCommunication between two or more nearby UEs without traversing anynetwork node.

UEs that are in proximity of each other can exchange V2V-relatedinformation when permission, authorization, and proximity criteria arefulfilled. The proximity criteria can be configured by the mobilenetwork operator (MNO). UEs supporting V2V Service can also exchangesuch information when served by or not served by an MNO that supportsV2X service. The UE supporting V2V applications transmits applicationlayer information, such as about a location, dynamics, and attributes,as part of the V2V service. The V2V payload can be flexible in order toaccommodate different information contents, and the information can betransmitted periodically according to a configuration provided by theMNO. V2V is predominantly broadcast-based; V2V includes the exchange ofV2V-related application information between distinct UEs directlyand/or, due to the limited direct communication range of V2V, theexchange of V2V-related application information between distinct UEs viainfrastructure supporting V2X service, such as RSU, application server,and so on.

FIG. 5 illustrates an example SL interface 500 according to illustrativeembodiments of the present disclosure. For example, the SL interface 500may be implemented among UEs in a wireless network, for example, asillustrated in FIG. 1. The embodiment of the SL interface 500 shown inFIG. 5 is for illustration only. Other embodiments of the SL interface500 can be used without departing from the scope of the presentdisclosure.

In this illustrative embodiment, UL designates the link from UE 501 togNB 503, DL designates the link from gNB 503 to UE 501, and SLdesignates the radio links over the PC5 interfaces between UE 501 andUEs 502. UE 501 transmits a V2V message to one or multiple UEs 502 inthe SL. The PC5 interface re-uses existing frequency allocation,regardless of the duplex mode (frequency division duplex (FDD) or timedivision duplex (TDD). To minimize a hardware complexity on a UE andespecially on the power amplifier of the UE, transmission on V2V linkscan occur in the UL band in case of FDD. Similar, the PC5 interface canuse time resources (symbols of slots) that are reserved for ULtransmission in TDD. The signal transmission can be based on singlecarrier frequency division multiple access (SC-FDMA) or on orthogonalfrequency division multiple access (OFDMA).

A sidelink can include transmissions of signals and channels as for adownlink or for an uplink. For example, similar to a downlink, asidelink includes transmission of a physical sidelink control channel(PSCCH) providing a sidelink control information (SCI) format schedulinga reception of a physical sidelink shared channel (PSSCH) providingTB(s) for data information and also includes transmission ofcorresponding DM-RS or of CSI-RS. For example, similar to uplink, asidelink includes a physical sidelink feedback channel (PSFCH) providingHARQ-ACK information in response to a decoding outcome of a TB in aPSSCH reception.

For a PSSCH transmission from a first UE to a second UE, the second UEcan report in a PSFCH HARQ-ACK information for a decoding outcome of TBprovided by the PSSCH reception. The HARQ-ACK information has an ACKvalue when the second UE correctly decodes the TB and a NACK value whenthe second UE does not correctly decode the TB. The first UE can reportthe HARQ-ACK information from the second UE to a serving gNB through theuplink.

In several scenarios, such as for example when a HARQ-ACK informationreception reliability cannot be ensured or when HARQ-ACK information maynot be useful as there may not be retransmissions of a TB, it can bebeneficial to dynamically disable reporting of HARQ-ACK information by aUE in response to a TB decoding in a PSSCH reception.

A first UE can transmit a PSSCH providing a TB to a second UE. The TBcan include one or more code block groups (CBGs) where each code block(CB) includes a CRC. The second UE can report whether or not each CBGincluded in the TB is correctly decoded. A CBG is correctly decoded whenall CBs included in the CBG are correctly decoded; otherwise, the CBG isincorrectly decoded. For a retransmission of the TB in a PSSCH, thefirst UE can include only CBGs with NACK value for HARQ-ACK informationcorresponding to a previous transmission of the TB.

FIG. 6 illustrates a first example of CBG-based HARQ-ACK informationreporting on sidelink according to various embodiments of the presentdisclosure. For example, the CBG-based HARQ-ACK information reportingmay be among the UEs in a sidelink as illustrated, for example, in FIG.5. The embodiment of the CBG-based HARQ-ACK information reporting shownin FIG. 6 is for illustration only. Other embodiments can be usedwithout departing from the scope of the present disclosure.

UE-A transmits a PSSCH to UE-B. A PSSCH transmission provides a TB and,with CBG-based HARQ-ACK information reporting from UE-B, PSSCHretransmissions for a TB provide CBGs (the CBGs that were indicated bythe HARQ-ACK information to have been incorrectly decoded by UE-B). UE-A601 can transmit a PSCCH with a SCI format 611 to schedule a PSSCHreception by UE-B 602. A TB in the PSSCH reception 612 includes fourCBGs: 621, 622, 623 and 624. After detecting the SCI format 611, UE-B602 can decode CBs in a corresponding PSSCH reception 612 according to aconfiguration provided by the SCI format 611. UE-B 602 decodes CBs ofeach CBG in the TB included in the PSSCH reception 612 and checks acorresponding CBG 621, 622, 623 and 624. UE-B reports HARQ-ACKinformation of a decoding outcome for each CBG 621, 622, 623 and 624 inone or more PSFCHs 613. In 613, the UE-B can report which ones of CBGs621, 622, 623 and 624 are decoded correctly. UE-A 601 can re-transmitCBGs that UE-A detects a corresponding HARQ-ACK information to have aNACK value. UE-A can indicate in a SCI format 614 scheduling aretransmission of TB in a PSSCH 615 that three of the four CBGs 621, 623and 624 are re-transmitted (the fourth CGB 622 is not retransmitted).

SL transmission and reception by a UE occur within resources assigned toone or more UEs in a group of UEs. A resource pool (RP) is a set ofresources assigned for sidelink operation and consists of slots in thetime domain and resource blocks in the frequency domain.

FIG. 7 illustrates an example resource pool 700 according to variousembodiments of the present disclosure. For example, the resource pool700 may be shared among the UEs in a sidelink as illustrated, forexample, in FIG. 5. The embodiment of the resource pool shown in FIG. 7is for illustration only. Other embodiments can be used withoutdeparting from the scope of the present disclosure.

A resource pool 700 is defined as follows:

(a) in the frequency domain, by parameters

-   -   PRBnum: defining a frequency range/bandwidth in a number of        physical RBs (PRB)    -   PRB start, PRBend: defining a location in frequency for the        number of PRBs

(b) in the time domain, by a bitmap that indicates slots available forSL transmissions

A pool of time-frequency resources is repeated with a period defined bya parameter SC-Period, for example in a number of slots or in a numberof milliseconds with range of possible values between 40 msec and 320msec where, for example, the smaller values can be used for voicetraffic.

UEs can scan a resource pool to receive PSCCH and detect a SCI formatthat includes a group identifier for the UEs. A UE transmits a PSCCHwith a SCI format within the resource pool.

Resource pools can be of two types: reception resource pools (Rx RPs)and transmission resource pools (Tx RPs). Within a cell, there may bemore Rx RPs than Tx RPs to enable reception from adjacent cells or fromout-of-coverage UEs.

Two modes of resource allocation exist for V2X communications: Mode 1that is also referred to as “scheduled resource allocation” and Mode 2that is also referred as “UE autonomous resource selection”. In Mode 1,transmissions on sidelink are scheduled by a gNB. The UE detects a DCIformat from the gNB that indicates resources for PSCCH/PSSCHtransmission and then the UE transmits a PSCCH with a SCI formatscheduling a PSSCH transmission over resources indicated by the DCIformat.

FIG. 8 illustrates a second example of CBG-based HARQ-ACK informationreporting on sidelink according to various embodiments of the presentdisclosure. For example, the CBG-based HARQ-ACK information reportingmay be among the UEs in a sidelink as illustrated, for example, in FIG.5. The embodiment of the CBG-based HARQ-ACK information reporting onsidelink shown in FIG. 8 is for illustration only. Other embodiments canbe used without departing from the scope of the present disclosure.

UE-A 802 transmits a PSSCH to UE-B 803 through sidelink. A sidelinkresource used for the PSSCH transmission is allocated to UE-A by aserving gNB, or BS, 801. The BS 801 can transmit a PDCCH to UE-A 802 toallocate, through a corresponding DCI format, to UE-A 802 the sidelinkresource for PSCCH and PSSCH transmissions. UE-A transmits a PSCCH and aPSSCH in the allocated sidelink resource. A TB included in a PSSCHreception 813 by UE-B comprises of four CBGs 821, 822, 823 and 824. UE-B803 detects a SCI format 812 in a PSCCH reception and then decodes theTB in a PSSCH reception 813 according to configuration informationprovided by the SCI format 812. UE-B decodes each CB for CBGs 821, 822,823 and 824 and then checks a corresponding CRC. UE-B 803 reportsHARQ-ACK information for each of the four CBGs in the PSSCH reception813 through one or more PSFCHs 814. UE-A can report the detectedHARQ-ACK information for the four CBGs 821, 822, 823 and 824 to theserving gNB 801 in a PUCCH or PUSCH transmission 815. The followingalternatives can apply for the HARQ-ACK information reports by UE-A in815:

-   -   UE-A can report a number of incorrectly decoded CBGs among the        four CBGs 821, 822, 823 and 824.    -   UE-A can report the incorrectly decoded CBGs among the four CBGs        821, 822, 823 and 824.    -   UE-A can report the correctly decoded CBGs among the four CBGs        821, 822, 823 and 824.    -   UE-A can report HARQ-ACK information for each of the four CBGs        821, 822, 823 and 824.

After a reception of a HARQ-ACK information report from UE-A 802, thegNB 801 can transmit a PDCCH 816 to UE-A to allocate, through a DCIformat in the PDCCH, a sidelink resource for UE-A 802 to retransmit in aPSSCH incorrectly decoded CBGs by UE-B. UE-A 802 can transmit a PSCCHwith a SCI format 817 scheduling a PSSCH reception 818 to UE-B thatincludes the incorrectly decoded CBGs 821, 823 and 824 using thesidelink resource allocated by the gNB 801. In the SCI format 817, UE-Acan indicate the CBGs, from the four CBGs 821, 822, 823 and 824, thatare included in the PSSCH reception 818.

A UE can transmit a PSCCH providing a SCI format that schedules one ormore PSSCH receptions to one or more other UEs. The SCI format caninclude one or more of the following information elements (fields):

-   -   A destination ID to identify a UE or a group of UEs for a        corresponding PSSCH reception;    -   A HARQ process number;    -   A source ID to identify a UE transmitting the PSCCH/PSSCH;    -   A new data indicator (NDI) to indicate whether the PSSCH        includes a first transmission or a retransmission of a TB;    -   A redundancy version (RV);    -   CBG transmission indicator to indicate initial transmission or        retransmission of a CBG in the PSSCH;    -   A SL_HARQ_Conf field to indicate whether reporting of HARQ-ACK        information for the TB/CBGs of the scheduled PSSCH reception is        enabled or disabled;    -   A resource allocation field for a PSFCH transmission with        HARQ-ACK information from a UE receiving the PSSCH.

The LTE-V and NR standards include two radio interfaces. The cellularinterface, Uu, supports vehicle-to-infrastructure communications. ThePC5 interface supports V2V communications based on direct LTE sidelink.LTE sidelink, or device-to-device communication, was introduced forpublic safety and includes two modes of operation, mode 1 and mode 2.Both modes were designed to prolong the battery lifetime of mobiledevices at the cost of increasing the latency. Connected vehiclesrequire highly reliable and low-latent V2X communications. Therefore,modes 1 and 2 may not be suitable for vehicular applications.

Two new communication modes, modes 3 and 4, are specifically designedfor V2V communications. In mode 3 (referred to as mode 1 in NR), thecellular network selects and manages the radio resources used byvehicles for their direct V2V communications. In mode 4 (referred to asmode 2 in NR), vehicles autonomously select the radio resources fortheir direct V2V communications. Mode 4 can operate without cellularcoverage and is therefore considered the baseline V2V mode becausesafety applications cannot effectively depend on the availability ofcellular coverage. Mode 4 includes a distributed scheduling scheme forvehicles to select their radio resources and includes the support fordistributed congestion control.

LTE V2X defines subchannels as a group of RBs in the same subframe. Thenumber of RBs per subchannel can vary. Subchannels are used to transmitdata and control information. The data is transmitted in transportblocks (TBs) over physical sidelink shared channels (PSSCH) and thesidelink control information (SCI) messages are transmitted overphysical sidelink control channels (PSCCH). A UE, such as the UE 116,that transmits a TB also transmits its associated SCI format that isalso referred to as a scheduling assignment. The SCI format includesinformation such as the modulation and coding scheme (MCS) used totransmit the TB, the frequency resource allocation, and the resourcereservation interval for semipersistent scheduling (SPS). A TB and itsassociated SCI format are always be transmitted in a same subframe. LTEV2X defines two sub-channelization schemes.

The first scheme is an adjacent PSCCH+PSSCH. The SCI format and TB aretransmitted in a respective PSCCH and PSSCH in adjacent RBs. For eachPSCCH and PSSCH transmission, the PSCCH occupies the first two RBs ofthe first subchannel utilized for the transmission. The PSSCH istransmitted in the RBs following the PSCCH and can occupy severalsubchannels, for example, depending on a size of a TB provided by thePSSCH. If the PSSCH occupies several subchannels, the PSSCH alsooccupies the first two RBs of the following subchannels.

The second scheme is a non-adjacent PSCCH+PSSCH. The RBs are dividedinto pools. One pool is dedicated to transmitting only PSCCHs and thePSCCHs occupy two RBs. The second pool is reserved to transmit onlyPSSCHs and is divided into subchannels.

NR V2X Release 16 introduced two communication modes, Mode 1 and Mode 2.In Mode 1, a gNB schedules SL resources to be used by a UE for SLtransmissions. In Mode 2, a UE determines SL transmission resource(s)within SL resources configured by a gNB/network or pre-configured SLresources. The UE autonomously selects the SL resource or resources fortransmission and schedules SL transmissions of other UEs. The UE furtherassists SL resource selection for other UEs which can be included inother UE functions.

The Medium Access Control (MAC) entity can be configured by RRC with adiscontinuous reception (DRX) functionality that controls the PDCCHmonitoring of the UE. When in RRC_CONNECTED, if DRX is configured, theMAC entity can instruct the physical layer of the UE to monitor PDCCHdiscontinuously using the DRX operation; otherwise the MAC entityinstructs the physical layer of the UE to monitor the PDCCHcontinuously.

For power control, a receiver UE reports SL-RSRP to the transmitter UEand, for sidelink open loop power control for unicast PSCCH/PSSCHtransmissions, the transmitter UE can derive a pathloss based on arespective reported SL-RSRP.

When HARQ-ACK information reporting is enabled for groupcast, a receiverUE transmits only HARQ-ACK information with NACK value (option 1) orHARQ-ACK information with either ACK value or NACK value (option 2). InHARQ-ACK information reporting for groupcast, all receiver UEs can sharea physical sidelink feedback channel (PSFCH) for Option 1, while eachreceiver UE can use a separate PSFCH for Option 2. Each PSFCH can bemapped to a time, frequency, and code resource.

Sidelink CSI-RS for CQI/RI measurement can be supported. The sidelinkCSI-RS can be confined within resources of the PSSCH transmission.Support can be provided at least for the use of TX-RX geographicaldistance in determining whether to report HARQ-ACK information forgroupcast.

In a resource pool and within the slots associated with the resourcepool, PSFCH resources can be (pre)configured periodically with a periodof N slot(s), N is configurable with values of 1 and at least one morevalue greater than 1. In addition, the configuration can include thepossibility of no resource for PSFCH such as for example configuring Nwith value 0. When the configuration includes the possibility of noresource for PSFCH, HARQ-ACK information reporting for all transmissionsin the resource pool can be disabled. In addition, a PSFCH with HARQ-ACKinformation for a PSSCH reception in a resource pool can be restrictedto only be transmitted in the same resource pool.

At least TDM between PSCCH/PSSCH and PSFCH can be supported and theremay be no simultaneous transmission of PSCCH/PSSCH and PSFCH.

SL open-loop power control can be supported. For unicast, groupcast,broadcast, open-loop power control can be based on the pathloss betweena transmitter UE and the gNB (DL pathloss), if the transmitter UE isin-coverage, at least to mitigate interference to UL receptions at thegNB. The gNB can enable and disable open-loop power control based on DLpathloss. At least for unicast, open-loop power control can also basedon the pathloss between a transmitter UE and a receiver UE (SLpathloss). Configuration or pre-configuration can enable or disableopen-loop power control based on the SL pathloss.

For sidelink transmit power control, a total sidelink transmit power canbe same in symbols used for PSCCH/PSSCH transmissions in a slot. Amaximum SL transmit power can be configured or preconfigured to atransmitter UE. For SL open-loop power control, a transmitter UE can beconfigured to use DL pathloss (between transmitter UE and gNB) only, SLpathloss (between transmitter UE and receiver UE) only, or both DLpathloss and SL pathloss. When the SL open-loop power control isconfigured to use both DL pathloss and SL pathloss, a minimum of thepower values given by open-loop power control based on DL pathloss andthe open-loop power control based on SL pathloss can be used.

Various embodiments of the present disclosure provide a method andapparatus for NR V2X sidelink communication aspects. More specifically,various embodiments of the present disclosure provide sidelink HARQ-ACKinformation reporting for groupcast, position information, signalingposition information, position information and data multiplexing in aPSSCH, associating PSCCH/PSSCH reception resources with PSFCHtransmission resources, TX-RX geographical distance based HARQ-ACKinformation reporting, and RSRP based HARQ-ACK information reporting.

As described herein, various embodiments of the present disclosureprovide a sidelink HARQ-ACK information reporting for groupcast. Forexample, sidelink HARQ-ACK information reporting for groupcast can beprovided when a receiver UE transmits only HARQ-ACK information withNACK value.

For sidelink HARQ-ACK information reporting only with NACK value, onePRB can be sufficient for the corresponding PSFCH transmission. Forexample, if multiple UEs share a same PSFCH, the in-band emission (IBE)may be high enough to constitute a larger interference to a neighboringfrequency resource. If a PSCCH/PSSCH transmission is over multiple PRBs,and even multiple subchannels, the associated number of PSFCHs can bemore than one. Then, the receiver UEs can share a pool of PSFCHs and asmaller number of UEs can transmit PSFCH. Accordingly, a resulting IBEcan become smaller.

In some embodiments, each receiver UE 116 randomly selects a PSFCHresource for transmission in the PSFCH pool. FIG. 9 illustrates randomselection by UEs of a PSFCH resource according to various embodiments ofthe present disclosure. The embodiment of random selection shown in FIG.9 is for illustration only. Other embodiments can be used withoutdeparting from the scope of the present disclosure.

As shown in FIG. 9, UE 1 selects PSFCH resource 1, UE 2 selects PSFCHresource n, UE 3 selects PSFCH resource 2, and UE K also selects PSFCHresource 2. Accordingly, each UE 1, 2, 3, and K randomly selects PSFCHresource 1, 2, or n in the PSFCH resource pool for PSFCH transmissionwith HARQ-ACK information having a NACK value. However, theseembodiments should not be construed as limiting and any random selectioncan be performed without departing from the scope of the presentdisclosure. As described herein, any of the UEs 1, 2, 3, or K can be anyof the UEs 111-118 described herein.

In some embodiments, receiver UEs can select a resource for a PSFCHtransmission according to predefined mapping rules. For example, if a UEID is assigned for each receiver UE by PC5-RRC, each receiver UE canselect a PSFCH resource in the PSFCH resource pool according topredefined mapping rules. The predefined mapping rules can map eachPSFCH resource in the PSFCH resource pool to each receiver UE. Thepredefined mapping rules can be obtained by a UE ID modulo a number ofPSFCH resources. In some embodiments, the predefined mapping rules canbe obtained and then stored in the memory 260 of the UE 116.

FIG. 10 illustrates selection by UEs of PSFCH resources according topredefined rules according to various embodiments of the presentdisclosure. In particular, FIG. 10 illustrates each UE selecting a PSFCHresource in the PSFCH resource pool for PSFCH transmission with HARQ-ACKinformation having a NACK value according to a pre-defined rule thatmaps each UE to a PSFCH resource in the PSFCH resource pool. Theembodiment of selection shown in FIG. 10 is for illustration only. Otherembodiments can be used without departing from the scope of the presentdisclosure.

As shown in FIG. 10, UE 1 and UE 3 each select PSFCH resource 1according to the predefined mapping rule and UE 2 and UE 4 each selectPSFCH resource 2 according to the predefined mapping rule.

In some embodiments, sidelink HARQ-ACK information reporting forgroupcast can include either an ACK value or a NACK value. In theseembodiments, each receiver UE 116 is implicitly assigned a separatePSFCH resource to report HARQ-ACK information. Because of limited PSFCHresources, one or more receiver UEs may not be assigned a separate PSFCHresource. Accordingly, in some scenarios, each receiver UE needs to usea separate PSFCH but there may not be enough PSFCH resources for allreceiver UEs.

In one embodiment, there can be a shared resource for PSFCH resource forPSFCH transmission with HARQ-ACK information having ACK value andanother shared PSFCH resource for PSFCH transmission with HARQ-ACKinformation having NACK value where receiver UEs that are not assigned adedicated PSFCH can use either resource for PSFCH transmission with ACKvalue or NACK value.

FIG. 11 illustrates assignments of UEs to PSFCH resources according tovarious embodiments of the present disclosure. The embodiment ofassignments shown in FIG. 11 is for illustration only. Other embodimentscan be used without departing from the scope of the present disclosure.

As shown in FIG. 11, UE 1 is assigned to PSFCH resource 1 and UE 2 isassigned to PSFCH resource 2. UE 3 and UE K are each assigned to PSFCHresource 3A for when the HARQ-ACK information has ACK value and to PSFCHresource 3N when the HARQ-ACK information has NACK value.

In another embodiment, all the receiver UEs can share one or a pool ofPSFCH resources for PSFCH transmission with HARQ-ACK information havingACK value and the other one or another pool of PSFCH resources for PSFCHtransmission with HARQ-ACK information having NACK value. In someembodiments, in a pool of PSFCH resources, the receiver UE can randomlyselect a resource from the pool. In other embodiments, the receiver UEcan select a first or second resource for HARQ-ACK information with ACKor NACK value, respectively, according to a mapping rule that maps eachUE to a PSFCH resource in the PSFCH pool according to the HARQ-ACKinformation value. For example, the mapping can be obtained by a UE IDmod (number of PSFCH resources), where the mod operation is Modulusafter division. In some embodiments, the mapping rules can be obtainedand then stored in the memory 260 of the UE 116.

FIG. 12 illustrates random selection by UEs of a resource for a PSFCHtransmission according to a HARQ-ACK information value according tovarious embodiments of the present disclosure. The embodiment of randomselection shown in FIG. 12 is for illustration only. Other embodimentscan be used without departing from the scope of the present disclosure.

As shown in FIG. 12, UEs 1 through K randomly select resource for PSFCHtransmission with HARQ-ACK information having ACK value and a resourcefor PSFCH transmission with HARQ-ACK information having NACK value froma pool of resources for PSFCH transmission with ACK value and a pool ofresources for PSFCH transmission with NACK value, respectively. Inparticular, UE 1 and UE 3 each randomly select PSFCH resource 1A (forACK value) and PSFCH resource 1N (for NACK value) and UE 2 and UE K eachrandomly select PSFCH resource 2A (for ACK value) and PSFCH resource 2Nfor NACK value. However, these embodiments should not be construed aslimiting and any random selection can be performed without departingfrom the scope of the present disclosure.

Some embodiments can include operations for sidelink HARQ-ACKinformation reporting for groupcast PSSCH where a receiver UE cantransmit HARQ-ACK information with ACK value or NACK value or only withNACK value. For example, each receiver UE can be implicitly assigned aseparate PSFCH resource to report HARQ-ACK information with ACK value orNACK value. Considering limited PSFCH resources, one or more receiverUEs may not be able to be assigned a separate PSFCH resource.

In one embodiment, there can be at least a shared PSFCH resource forHARQ-ACK transmission with only NACK value where receiver UEs that arenot assigned a dedicated PSFCH resource can use the shared resource forPSFCH transmission with only NACK value.

FIG. 13 illustrates assignments of UEs to PSFCH resources according tovarious embodiments of the present disclosure. The embodiment of theassignments shown in FIG. 13 is for illustration only. Other embodimentscan be used without departing from the scope of the present disclosure.

As shown in FIG. 13, UE 1 is assigned to PSFCH resource 1 and UE 2 isassigned to PSFCH resource 2. UE 3 through UE K are assigned to PSFCHresource 3N for PSFCH transmission with only NACK value.

Various embodiments of the present disclosure provide positioninformation of a receiver UE and transmitter UE. For TX-RX geographicaldistance based HARQ-ACK information reporting, the receiver UE within acertain distance from the transmitter UE transmits PSFCH with HARQ-ACKinformation to the transmitter UE, whereas the receiver UE beyond thecertain distance from the transmitter UE does not transmit PSFCH to thetransmitter UE. To support Tx-Rx geographical distance based HARQ-ACKinformation reporting, the receiver UE needs to know positioninformation for the transmitter UE. The receiver UE can then calculatethe distance from the transmitter UE based on the position informationreceived from the transmitter UE. As described herein, both the receiverUE and the transmitter UE can be any of the UEs 111-115. In variousembodiments, at least one of the receiver UE and the transmitter UE canbe the UE 118 when the various embodiments are implemented in V2Xcommunication.

In some embodiments, the position information can be GPS positioninformation. For example, the position information can be GPS DD(decimal degrees) or DMS (degrees, minutes, seconds) locationinformation with full or reduced precision. For GPS information, 1degree is equal to 60 minutes, and 1 minutes is equal to 60 seconds.Decimal Degrees=degrees+(minutes/60)+(seconds/3600).

Various embodiments of the present disclosure provide mechanisms forsignaling position information of a receiver UE and a transmitter UE. Tosupport Tx-Rx geographical distance based HARQ-ACK informationreporting, position information of the transmitter UE is signaled to thereceiver UE. Various approaches allow the position information to besignaled from the transmitter UE to the receiver UE.

In some embodiments, the position information can require a few tens ofbits. The position information is not signaled frequently because theposition of the UE may not change significantly within seconds.Reserving a few tens of bits in a SCI format provided by a PSCCH ismaterial overhead. Therefore, the position information of thetransmitter UE can be included in a PSSCH. A field of one bit in the SCIformat provided by a PSCCH scheduling a PSSCH can indicate presence orabsence of the position information of the transmitter UE. When the bitof the field indicates presence of the position information, thereceiver UE extracts the position information from the PSSCH and usesthe position information to calculate the distance from the transmitterUE. When the bit of the field indicates absence of the positioninformation, the receiver UE does not extract the position informationfrom the PSSCH reception.

FIG. 14 illustrates a field in a SCI format provided in a PSCCHreception indicating presence or absence of position information in aPSSCH reception scheduled by the SCI format according to variousembodiments of the present disclosure. The embodiment shown in FIG. 14is for illustration only. Other embodiments can be used withoutdeparting from the scope of the present disclosure.

As shown in FIG. 14, the SCI format in a PSCCH reception indicatespresence or absence of the position information in a PSSCH receptionscheduled by the SCI format.

In other embodiments, each PSSCH reception can include positioninformation. For example, presence or absence of position information ina PSSCH reception can be configured by higher layers and stored in thememory 260. As another example, each PSSCH reception can always includeposition information.

In other embodiments, a SCI format includes a first stage SCI format anda second stage SCI format, and the second stage SCI format provides theposition information. Further, presence or absence of the positioninformation in the second stage SCI format can be indicated by the firststage SCI format.

Various embodiments of the present disclosure provide mechanisms formultiplexing position information and data information in a PSSCH. Theposition information can be encoded separately from the data informationand then multiplexed with the data information in a same PSSCH. For themapping on resource elements of the PSSCH, the encoded data informationis rate matched to the encoded position information. The encodedposition information bits can be mapped on one or some of the PSSCHresource elements. When a CSI report, CSI-RS, or PTRS exists in a samePSSCH, resource elements for the encoded position information bits donot overlap with the resource elements for the CSI report, or theCSI-RS, or the PTRS. In various embodiments, for encoding positioninformation, when position information bits are between 3 and 11, ReedMuller Code can be used and when position information bits are more than11 bits, Polar code can be used.

In other embodiments, the position information can be provided by aMAC-CE message in the PSSCH.

In other embodiments, the position information can be provided by an RRCmessage in the PSSCH.

Various embodiments of the present disclosure provide mechanisms toassociate PSCCH/PSSCH resources with PSFCH resources. In particular,various embodiments of the present disclosure support, in a resourcepool and within slots associated with the resource pool, PSFCH resourcesto be (pre)configured periodically with a period of N slot(s). In someembodiments, the entire bandwidth of subchannels can be used for PSFCHresources at slots where PSFCH resources are configured.

If the period of PSFCH transmission is N=1 slot, PSFCH resources areassociated with a number of PRBs equal to the PSCCH/PSSCH subchannelsize in PRBs. For a PSCCH/PSSCH transmission over more than onesubchannel, PSFCH resources corresponding to PRBs over all subchannelsallocated for PSCCH/PSSCH.

FIG. 15 illustrates a mapping between PSCCH/PSSCH resources and PSFCHresources according to various embodiments of the present disclosure.The embodiment shown in FIG. 15 is for illustration only. Otherembodiments can be used without departing from the scope of the presentdisclosure.

As shown in FIG. 15, the PSCCH/PSSCH resource can have associated PSFCHresources in the same frequency resources. The PSFCH resources areillustrated in the same shade as the associated PSCCH/PSSCH resource andeach PSCCH/PSSCH subchannel is represented by a separate block.

FIG. 16 illustrates a mapping of PSCCH/PSSCH resources to PSFCHresources according to various embodiments of the present disclosure.The embodiment shown in FIG. 16 is for illustration only. Otherembodiments can be used without departing from the scope of the presentdisclosure.

As shown in FIG. 16, a PSCCH/PSSCH reception can be over multiplesubchannels and associated PSFCH resources are mapped to the samefrequency resources as for the multiple subchannels. In other words, theassociated PSFCH resources correspond to a same number of PRBs as forthe subchannels of the PSCCH/PSSCH reception. In FIG. 16, PSFCHresources are shown in the same shade as the associated resources for acorresponding PSCCH/PSSCH reception, each PSCCH/PSSCH subchannel isrepresented by a block, and each same PSCCH/PSSCH subchannel is markedin the same shade.

In some embodiments, the associated PSFCH resource may not necessarilybe located in a same frequency resource as a subchannel for acorresponding PSCCH/PSSCH reception. For example, a PSFCH resource canbe located in a subchannel that has an offset in frequency to asubchannel of the associated PSCCH/PSSCH reception. The offset infrequency can be preconfigured or configured by higher layers.

In some embodiments, a PSFCH resource associated with a PSCCH/PSSCHreception may not be located in a same time slot as the PSCCH/PSSCHreception. For example, the PSFCH resource can be located in a slot thathas a slot offset to the slot of the PSCCH/PSSCH reception. The slotoffset can be preconfigured or configured by higher layers. The UEtransmits a PSFCH in a first slot that is after a slot of a PSCCH/PSSCHreception by a number of slots equal to the slot offset and has anallocation for PSFCH resources.

In some embodiments, when a period of PSFCH resources is N>1 slot, eachPSCCH/PSSCH subchannel can be associated with only a part of the numberof PRBs of a subchannel of an associated PSCCH/PSSCH reception. AllPSCCH/PSSCH subchannels over N slots that are associated with PSFCHresources in a same subchannel share a same PSFCH resource pool in asame subchannel. For a PSCCH/PSSCH reception over more than onesubchannel, the number of PSFCH resources that are allocated are thenumber of associated PRBs in each PSCCH/PSSCH subchannel multiplied bythe number of PSCCH/PSSCH subchannels.

FIG. 17 illustrates a mapping of PSCCH/PSSCH resources with associatedPSFCH resources in different slots according to various embodiments ofthe present disclosure. The embodiment shown in FIG. 17 is forillustration only. Other embodiments can be used without departing fromthe scope of the present disclosure.

As shown in FIG. 17, a PSCCH/PSSCH reception can have associated PSFCHresources in same frequency resources. The PSFCH resources are shown inthe same shade as the associated PSCCH/PSSCH resources, each PSCCH/PSSCHsubchannel is represented by a block, and PSCCH/PSSCH subchannels indifferent slots are associated with the pool of PSFCHs in a samesubchannel.

In some embodiments, the PSFCH resources may not be located in a samefrequency resource as the associated PSCCH/PSSCH resources. For example,the PSFCH resource can be located in a subchannel that has an offset infrequency to the subchannel of the associated PSCCH/PSSCH reception. Theoffset in frequency can be preconfigured or configured by higher layers.

In some embodiments, the PSFCH resource may not be located in the sametime slot as the associated PSCCH/PSSCH reception. For example, thePSFCH resource can be located in a slot that has a slot offset to theslot of the associated PSCCH/PSSCH reception. The slot offset can bepreconfigured or configured by higher layers. The UE transmits a PSFCHin a first slot that is after a slot of a PSCCH/PSSCH reception by anumber of slots equal to the slot offset and has an allocation for PSFCHresources.

The PSCCH/PSSCH subchannels in N slots that are associated with thePSFCH resources in a same subchannel can share a same PSFCH resourcepool in a same subchannel.

In one embodiment, a PSCCH/PSSCH subchannel in slot i is associated withPSFCH resources in the PRBs that have a PRB index in a subchannel N*k+imod (subchannel size in number of PRBs), where mod operation is Modulusafter division and k is integer and where the PRB index is valid in asubchannel.

FIG. 18 illustrates a mapping between a PSCCH/PSSCH subchannel in a slotand a PSFCH resource according to various embodiments of the presentdisclosure. The embodiment shown in FIG. 18 is for illustration only.Other embodiments can be used without departing from the scope of thepresent disclosure.

In FIG. 18, PSFCH resources exist with a period of N=2 slots and anumber of PRBs in a subchannel is 4. PRB 0 and 2 are associated with aPSSCH reception in slot i and PRB 1 and 3 are associated with a PSSCHreception in slot i+1.

In another embodiment, a PSCCH/PSSCH subchannel in slot i is associatedwith PSFCH resources in PRBs that have a PRB index in a subchannel: imod (subchannel size in number of PRBs)*X+k, where the mod operation isModulus after division and k is from 0 to X−1. X can be a floor for theratio of subchannel size in number of PRB s divided by N, or a ceilingfor the ratio of subchannel size in number of PRBs divided by N.

FIG. 19 illustrates a mapping for a PSCCH/PSSCH subchannel in a slot toPSFCH resources according to various embodiments of the presentdisclosure. The embodiment shown in FIG. 19 is for illustration only.Other embodiments can be used without departing from the scope of thepresent disclosure.

In FIG. 19, PSFCH resources exist with a period of N=2 slots and anumber of PRBs in a subchannel is 4. PRB 0 and 1 are associated with aPSSCH reception in slot i and PRB 2 and 3 are associated with a PSSCHreception in slot i+1.

Other embodiments can utilize similar principles as illustrated in FIGS.18 and 19. For example, a PSFCH resource is characterized by time,frequency, and code resource. Each PSFCH resource in terms of time,frequency, and code resource is configured to be associated with aPSCCH/PSSCH reception.

Various embodiments of the present disclosure provide TX-RX geographicalbased HARQ-ACK information reporting and/or RSRP based HARQ-ACKinformation reporting. For TX-RX geographical distance based HARQ-ACKinformation reporting, a receiver UE within a distance from atransmitter UE transmits a PSFCH with HARQ-ACK information to thetransmitter UE. In contrast, a receiver UE beyond a distance from thetransmitted UE does not transmit a PSFCH to the transmitter UE. For RSRPbased HARQ-ACK information reporting, a receiver UE having RSRP from atransmitter UE larger than a predetermined RSRP value transmits a PSFCHwith HARQ-ACK information to the transmitter UE. In contrast, a receiverUE having RSRP from the transmitter UE smaller than a predetermined RSRPvalue does not transmit PSFCH to the transmitter UE.

In some embodiments, one HARQ-ACK information reporting method may benot sufficient. For example, only zone ID information may be provided ina SCI format or in a PSSCH from a transmitter UE. The receiver UEderives an estimate of the distance from the transmitter UE based uponthe zone ID transmitted from the transmitter UE in the SCI format or inthe PSSCH.

FIG. 20 illustrates UEs marked in various geographical zones accordingto various embodiments of the present disclosure. The embodiment of theUEs shown in FIG. 20 is for illustration only. Other embodiments can beused without departing from the scope of the present disclosure.

In FIG. 20, when the receiver UE is located in Zone 2 marked in shade,the receiver UE receives PSCCH/PSSCH from the transmitter UE located inZone 1 marked in shade. Based upon the Zone ID information in a SCIformat or in a PSSCH received from the transmitter UE, the receiver UEderives a distance from the transmitter UE and determines that thedistance is small because Zone 2 and Zone 1 are neighboring zones. Then,the receiver UE determines to transmit a PSFCH with HARQ-ACKinformation. However, the actual distance value between the transmitterUE and the receiver UE can be large. Accordingly, various embodiments ofthe present disclosure provide TX-RX geographical based HARQ-ACKinformation reporting and/or RSRP based HARQ-ACK information reporting.

In some embodiments, a RSRP between the transmitter UE and receiver UEcan be used as an additional decision metric for a distance between areceiver UE and a transmitter UE. The receiver UE can determine whetherto transmit PSFCH with HARQ-ACK information to the transmitter UE basedon the distance information derived from the zone ID but also based onthe RSRP. The procedure can be defined as:

If the distance between a transmitter UE and a receiver UE derived from,for example, a Zone ID provided in a SCI format scheduling a PSSCHreception by the receiver UE is below a predetermined distance value

-   -   if the RSRP between the transmitter UE and the receiver UE is        larger than a predetermined RSRP value        -   the receiver UE transmits PSFCH with HARQ-ACK information to            the transmitter UE    -   else        -   the receiver UE does not transmit PSFCH to the transmitter            UE    -   end

end

else

-   -   if the RSRP between the transmitter UE and the receiver UE is        larger than a predetermined RSRP value        -   the receiver UE transmits a PSFCH with HARQ-ACK information            to the transmitter UE    -   else        -   the receiver UE does not transmit PSFCH to the transmitter            UE    -   end

end

As described herein, various embodiments of the present disclosureprovide PSFCH resource association for unicast and groupcast HARQ-ACKinformation reporting Option 1 with and without reservation signal,indication of a HARQ-ACK information reporting option for Groupcast andUnicast, and multiple HARQ-ACK information reporting for a same UE.

For example, embodiments of the present disclosure provide a PSFCHresource association for unicast and groupcast HARQ-ACK informationreporting Option 1 without a reservation signal. These embodimentsinclude indicating a PSFCH frequency resource by a SCI format schedulingan associated PSSCH reception from a set of PSFCH frequency resources.The PSFCH frequency resource can be (pre)configured or predefined. ThePSFCH frequency resource can be (pre)configured from a set of PSFCHfrequency resources.

Embodiments of the present disclosure further provide PSFCH resourceassociation for unicast and groupcast HARQ-ACK information reportingOption 1 with a reservation signal. The PSFCH frequency resource isindicated by an associated reservation signal from a set of PSFCHfrequency resources.

Embodiments of the present disclosure further provide an indication fora HARQ-ACK information reporting option for groupcast and for unicastPSSCH receptions. The HARQ-ACK information reporting option forgroupcast can be indicated by a SCI format scheduling an associatedPSSCH reception. When the reservation signal is used to reserveresources for transmission, the HARQ-ACK information reporting optioncan be indicated by an associated reservation signal. For unicast, a SCIformat scheduling an associated PSSCH reception can indicate whether thePSCCH/PSSCH is a unicast type or a groupcast type. When the reservationsignal is used to reserve resources for transmission, the reservationsignal can be used to indicate whether a PSCCH/PSSCH reception is aunicast type or a groupcast type.

Embodiments of the present disclosure further provide mechanisms formultiple PSFCH transmissions with respective multiple HARQ-ACKinformation to a same UE. The PSFCH frequency resources that can be usedfor transmission of the multiple PSFCHs can be (pre)configured orpredefined. The PSFCH frequency resource for the multiple PSFCHtransmissions can be indicated by the SCI format scheduling theassociated PSSCH receptions with corresponding HARQ-ACK informationprovided by PSFCH transmissions in a same PSFCH period. When areservation signal is used to reserve PSCCH/PSSCH/PSFCH resources, thePSFCH frequency resource used for multiple PSFCH transmissions can beindicated by the reservation signal that indicates the associatedPSCCHs/PSSCHs with corresponding HARQ-ACK information provided by PSFCHtransmissions in a same PSFCH transmission period.

As described herein, various embodiments of the present disclosureprovide a PSFCH resource association HARQ-ACK information reportingOption 1 for unicast and groupcast. There may be multiple PSFCHresources implicitly associated with PSSCH/PSSCH reception of unicasttype or groupcast type for HARQ-ACK information reporting Option 1 in aPSFCH period (N>1) of slots, but only one PSFCH resource is used forPSFCH transmission with the HARQ-ACK information. Accordingly, theseembodiments of the present disclosure recognize and take into accountthe need to specify a PSFCH resource for a UE to use for PSFCHtransmission with HARQ-ACK information when there are multipleimplicitly associated PSFCH resources for a PSSCH/PSSCH reception.

In one embodiment, the PSFCH frequency resource can be indicated by aSCI format scheduling an associated PSSCH reception. The PSFCH frequencyresource indicated by the SCI format may be selected from a set ofimplicitly associated PSFCH frequency resources. When a receiver UE doesnot receive or detect the SCI format, the receiver UE can still use theimplicitly associated PSFCH frequency resources to transmit PSFCHwithout any resource conflict.

FIG. 21 illustrates an association between a PSCCH/PSSCH reception at asubchannel in a slot and a corresponding PSFCH resource according tovarious embodiments of the present disclosure. The embodiment shown inFIG. 21 is for illustration only. Other embodiments can be used withoutdeparting from the scope of the present disclosure.

As shown in FIG. 21, PSCCH/PSSCH reception at sub-channel 1 in slot nhas implicitly associated PSFCH resources 1 and 2 in slot n+k and aPSCCH/PSSCH reception at sub-channel 1 in slot n+1 has implicitlyassociated PSFCH resources 3 and 4 in slot n+k. If the PSCCH/PSSCHreception at sub-channel 1 in slot n is unicast type or groupcast typewith HARQ-ACK information reporting Option 1, only one resource is needfor a PSFCH transmission with HARQ-ACK information in response to thePSCCH/PSSCH reception. If the associated PSFCH resource 1 in slot n+k isindicated by the SCI format provided by the PSCCH reception atsub-channel 1 in slot n, the other PSFCH resources 2, 3, and 4 in slotn+k can be used for PSFCH transmissions to other UEs that transmitPSCCH/PSSCH at sub-channel 1 in slot n+1.

The PSFCH frequency resource that the SCI format indicates amongimplicitly associated PSFCH resources can be the PRB index or a PRBgroup index in a subchannel if a UE is configured for PSFCH transmissionover one PRB or over multiple PRBs, respectively. For a sub-channel sizeof 4 PRBs, two PRBs are implicitly associated with a PSCCH/PSSCHreception. Accordingly, one bit in the SCI format can indicate the PRBindex within the implicit set. For example, a bit value of 0 indicatesthe 1^(st) PRB index and a bit value 1 indicates the 2^(nd) PRB index inthe implicitly associated PSFCH resources. For example, as shown in FIG.21, PRB index 1 is indicated by the SCI format scheduling an associatedPSSCH reception. Therefore, the PSFCH frequency resource in the firstPRB in the subchannel of implicitly associated PSFCH resources is usedfor HARQ-ACK information reporting in a PSFCH transmission. When the PRBgroup index is used for indication, 0 indicates the 1^(st) PRB group(1^(st) PRB index and 2^(nd) PRB index in the implicit set of thesub-channel of PSFCH) and 1 indicates the 2^(nd) PRB group (3^(rd) PRBindex and 4^(th) PRB index in the implicit set of the sub-channel ofPSFCH). The PSFCH resource that is indicated by the SCI format can beonly in the frequency domain, or either in the frequency domain or codedomain resource (e.g., cyclic shift of a sequence), or in both frequencyand code domains.

In another embodiment, the PSFCH frequency resource can be(pre)configured or predefined. The PSFCH frequency resource can be(pre)configured from a set of implicitly associated PSFCH frequencyresources. The PSFCH frequency resource that can be (pre)configured maybe selected from a set of implicitly associated PSFCH frequencyresources. The SCI format scheduling a PSSCH reception indicates whetherthe PSSCH reception is of unicast type, of groupcast type with HARQ-ACKinformation reporting Option 1, or groupcast HARQ-ACK informationreporting Option 2. When decoding the associated SCI format, other UEscan know the PSFCH frequency resource to be used from the(pre)configuration.

For example, by (pre)configuration or predefinition, the 1^(st) PRBindex in the implicitly associated PSFCH resources is used to transmitPSFCH for unicast type and groupcast type with HARQ-ACK informationreporting Option 1 in a PSFCH period of N>1 slots. Similar, the PSFCHresource that is (pre)configured can be either in the frequency domain,or in code domain resource (e.g., cyclic shift of a sequence), or inboth domains.

As described herein, various embodiments of the present disclosureprovide a reservation signal to indicate a PSFCH resource. Thereservation signal can be transmitted a few slots prior to a PSCCH/PSSCHtransmission to indicate a reserved PSCCH/PSSCH resource for thetransmission. Multiple PSFCH resources can be implicitly associated withPSSCH/PSSCH for unicast type and groupcast type HARQ-ACK informationreporting Option 1 in a PSFCH period of N>1 slots, but only one PSFCHresource is used for PSFCH transmission with corresponding HARQ-ACKinformation. A reservation signal can be used to indicate a PSFCHresource for the receiver UE(s) to use for PSFCH transmission among aset of implicitly associated PSFCH frequency resources. When a second UEreceives and decodes the reservation signal to obtain the PSFCH resourceinformation, the second UE can use the remaining PSFCH frequencyresources in the same PSFCH slot for a PSFCH transmission.

FIG. 22 illustrates an association of PSFCH resources reserved by areservation signal with a PSCCH/PSSCH reception in a subchannel in aslot according to various embodiments of the present disclosure. Theembodiment shown in FIG. 22 is for illustration only. Other embodimentscan be used without departing from the scope of the present disclosure.

As shown in FIG. 22, a PSCCH/PSSCH reception at sub-channel 1 in slot nhas implicitly associated PSFCH resources 1 and 2 in slot n+k and aPSCCH/PSSCH at sub-channel 1 in slot n+1 has implicitly associated PSFCHresources 3 and 4 in slot n+k. If the PSCCH/PSSCH reception atsub-channel 1 in slot n is unicast type or groupcast type with HARQ-ACKinformation reporting Option 1, one PSFCH resource is needed by thereceiver UE to transmit a PSFCH with corresponding HARQ-ACK information.The PSCCH/PSSCH resource at sub-channel 1 in slot n is reserved by areservation signal in slot n-p. If the associated PSFCH resource 1 or 3in slot n+k is indicated by the reservation signal in slot n-p, thePSFCH resources 2, 3, and 4 in slot n+k can be used by other UEs totransmit PSFCH. Compared with embodiments that do not include areservation signal, other UEs can have more time to determine availablePSFCH resources because that information can be obtained by decoding areservation signal that is received a few slots earlier than theassociated PSCCH/PSSCH reception.

In some embodiments, a PSFCH frequency resource that a reservationsignal indicates among implicitly associated PSFCH resources can be aPRB index or a PRB group index in a subchannel if a PSFCH transmissioncan be configured to be over one PRB or over multiple PRBs. For example,as shown in FIG. 22, the PRB index 1 is indicated in the reservationsignal, so the PSFCH frequency resource in the first PRB in thesubchannel of implicitly associated PSFCH resources is used for PSFCHtransmission with HARQ-ACK information.

In embodiments where the PRB group index is used for indication, a bitvalue of 0 can indicate the 1^(st) PRB group (1^(st) PRB index and2^(nd) PRB index in the implicit set of the sub-channel of PSFCH) and abit value of 1 can indicate the 2^(nd) PRB group (3^(rd) PRB index and4^(th) PRB index in the implicit set of the sub-channel of PSFCH). ThePSFCH resource that is indicated by a reservation signal can be eitherin the frequency domain, or in the code domain (e.g., cyclic shift of asequence), or in both the frequency and code domains.

As described herein, various embodiments of the present disclosureprovide an indication for a HARQ-ACK information reporting option forgroupcast and unicast. In some embodiments, there can be two HARQ-ACKinformation reporting options for groupcast, and one option can beindicated by a SCI format scheduling an associated PSSCH reception. Amotivation for the HARQ-ACK information reporting option for groupcastto be indicated by a SCI format scheduling an associated PSSCH receptionis that when s number of receiver UEs is more than s maximum number ofPSFCH resources in an associated PSFCH slot, s transmitter UE can notifythe receiver UEs to use HARQ-ACK information reporting Option 1.Otherwise, HARQ-ACK information reporting Option 2 can be indicated bythe transmitter UE to be used by the receiver UEs. When a reservationsignal is used to reserve resources for transmission, the HARQ-ACKinformation reporting option can be indicated by the associatedreservation signal.

For unicast, a SCI format in a PSCCH reception that schedules a PSSCHreception can indicate whether or not the PSCCH/PSSCH reception is ofunicast type. When a reservation signal is used to reserve resources forPSCCH/PSSCH transmission, the reservation signal can be used to indicatewhether or not the PSCCH/PSSCH reception is of unicast type.

As described herein, various embodiments of the present disclosureprovide mechanisms for a receiver UE to report multiple HARQ-ACKinformation bits to a transmitter UE. When multiple HARQ-ACK informationbits are reported to a transmitter UE, there may be multiple implicitlyassociated PSFCH resources, for example in different sub-channels, in asame PSFCH period of N>1 slots. If only one PSFCH resource can be usedfor reporting of multiple HARQ-ACK information bits in each slot, theone PSFCH resource should be specified.

FIG. 23 illustrates a determination for a PSFCH recourse in response tomultiple PSCCH/PSSCH receptions according to various embodiments of thepresent disclosure. The embodiment shown in FIG. 23 is for illustrationonly. Other embodiments can be used without departing from the scope ofthe present disclosure.

A PSCCH/PSSCH reception at sub-channel 1 in slot n has implicitlyassociated PSFCH resources in sub-channel 1. A PSCCH/PSSCH reception atsub-channel 2 in slot n+1 has implicitly associated PSFCH resources insub-channel 2. The PSCCH/PSSCH receptions in both slots are transmittedfrom a same transmitter UE, are received by a same receiver UE, and theassociated PSFCH resources for both receptions are in a same slot. Whenthe receiver UE provides multiple HARQ-ACK information bits to thetransmitter UE, the PSFCH resource that is indicated by an associatedreservation signal can be either in the frequency domain, or in the codedomain resource (e.g., cyclic shift of a sequence), or in both frequencyand code domains.

In some embodiments, a PSFCH frequency resource that can be used for aPSFCH transmission with multiple HARQ-ACK information bits can be(pre)configured or predefined. For example, the PSFCH frequency resourcefor transmission can be associated with a last PSCCH/PSSCH reception, ora first received PSCCH/PSSCH reception. For example, as shown in FIG.23, by (pre)configuration or predefinition, the PSFCH frequency resourcefor PSFCH transmission is respectively associated with the PSCCH/PSSCHreception at sub-channel 1 in slot n, or the PSCCH/PSSCH reception atsub-channel 2 in slot n+1 when the PSFCH frequency resource for PSFCHtransmission is associated with the last received PSCCH/PSSCH or thefirst received PSCCH/PSSCH.

In other embodiments, a PSFCH frequency resource for PSFCH transmissionwith multiple HARQ-ACK information bits can be indicated by a SCI formatin an associated PSCCH/PSSCH reception. When a receiver UE fails todetect a SCI format in a PSFCH period of N>1 slots, the receiver UE canstill use the correct PSFCH resource for transmission. The PSFCHfrequency resource is indicated by a slot index in the PSFCH period ofN>1 slots. For example, a slot index with value 0 indicates the firstslot in the PSFCH period for a PSFCH transmission.

FIG. 24 illustrates an indication of a second slot for a PSFCHtransmission in response to a PSCCH/PSSCH reception at a subchannel in afirst slot according to various embodiments of the present disclosure.The embodiment shown in FIG. 24 is for illustration only. Otherembodiments can be used without departing from the scope of the presentdisclosure.

As shown in FIG. 24, the PSFCH frequency resource for PSFCH transmissionin a second slot is associated with a PSCCH/PSSCH reception atsub-channel 1 in a first slot by an indication in each associatedPSCCH/PSSCH (i.e., PSCCH/PSSCH at sub-channel 1 in slot n andPSCCH/PSSCH at sub-channel 2 in slot n+1).

In other embodiments, when a reservation signal is used to reservePSCCH/PSSCH/PSFCH resources, the reservation signal can indicate a PSFCHfrequency resource for a PSFCH transmission with multiple HARQ-ACKinformation bits. The PSFCH frequency resource is indicated by a slotindex in the PSFCH period of N>1 slots. For example, a slot index withvalue 0 indicates that the implicitly associated PSFCH for thePSCCH/PSSCH in the first slot in the PSFCH period is used for PSFCHtransmission.

FIG. 25 illustrates an indication by a reservation signal of a secondslot for PSFCH transmission in response to a PSCCH/PSSCH reception at asubchannel in a first slot according to various embodiments of thepresent disclosure. The embodiment shown in FIG. 25 is for illustrationonly. Other embodiments can be used without departing from the scope ofthe present disclosure.

As shown in FIG. 25, the PSFCH frequency resource for a PSFCHtransmission in response to an associated PSCCH/PSSCH reception atsub-channel 1 in slot n is indicated by each associated reservationsignal (i.e., reservation signal for PSCCH/PSSCH reception atsub-channel 1 in slot n and PSCCH/PSSCH reception at sub-channel 2 inslot n+1).

As described herein, various embodiments of the present disclosureprovide mechanisms for PSFCH power control, power control parameterconfiguration, CSI-RS power control, CSI-RS transmission/reception, CSIreporting, power control for a reservation signal, configuration of amaximum UE transmit power, power sharing between uplink and sidelinktransmissions, and power sharing between transmissions with resourceallocation Mode 1 and Mode 2. The various embodiments can be implementedin a UE, such as the UE 116, for NR V2X power control and for a NR V2Xsidelink HARQ procedure.

For example, embodiments of the present disclosure include PSFCH powercontrol. In these embodiments, for groupcast HARQ-ACK informationreporting Option 1, the α_(sl) and/or P_(O_PSFCH_sl) is configured byPC5 higher layer signaling and the α_(sl) and/or P_(O_PSFCH_sl) isconfigured/indicated by a DCI format. The α_(sl) and/or P_(O_PSFCH_sl)for a receiver UE is separately configured from the power controlparameters for transmission of PSCCH/PSSCH channels.

Embodiments of the present disclosure further include power controlparameter configurations. In these embodiments, α_(sl), P_(O_sl), α_(c),and P_(O_c) are configured based on a zone where a UE is located.

Embodiments of the present disclosure further include CSI-RS powercontrol, where a CSI-RS transmission power is either fixed or indicated.

Embodiments of the present disclosure further include triggering of aCSI-RS transmission where a SCI format scheduling a PSSCH transmissioncan indicate whether or not a CSI-RS is also transmitted. Embodiments ofthe present disclosure further include CSI reporting where a SCI formatcan indicate whether a CSI-RS report is included in a PSSCHtransmission.

Embodiments of the present disclosure further provide power control fora reservation signal transmission. In these embodiments, the power ofthe reservation signal can be calculated by the open-loop power controlbased on DL pathloss only when DL pathloss is available. Theconfiguration of power control parameters for a reservation signal canbe separate from the configuration for other channels such asPSCCH/PSSCH, or PSFCH.

Embodiments of the present disclosure further provide a configurationfor a maximum UE transmit power PC_(MAX)·P_(CMAX) can depend on aservice type, priority of service, or channel status, and can beconfigured accordingly. Embodiments of the present disclosure furtherprovide power sharing between uplink and sidelink transmissions by a UEby considering one or more of priorities, interference, and congestion.Embodiments of the present disclosure further provide power sharingbetween two modes, described herein as Mode 1 and Mode 2, by consideringone or more of priorities, interference, and congestion.

As described herein, various embodiments of the present disclosureprovide mechanisms for PSFCH power control. For HARQ-ACK informationreporting Option 1 for groupcast, the receiver UE, such as the UE 116,transmits only HARQ-ACK information with value NACK to the transmitterUE, such as one of the UEs 111-115 and 118. Because the HARQ-ACKinformation with value NACK from different receiver UEs is transmittedin a same PSFCH resource, the sidelink interference caused by the PSFCHtransmissions in the PSFCH resource to neighboring RBs can be large.Accordingly, the sidelink pathloss from the transmitter UE to differentreceiver UEs is included in the power control formula, shown in Equation1.P _(PSFCH)=min(P _(CMAX) ,P _(O_PSFCH_c)+10 log₁₀(2^(μ) ·M_(PSFCH))+α_(c) ·PL _(c) ,P _(O_PSFCH_sl)+10 log₁₀(2μ·M _(PSFCH))+α_(sl)·PL _(sl))[dBm]  Equation 1

In Equation 1, P_(PSFCH) is the PSFCH transmission power, P_(CMAX) is amaximum (pre)configured UE transmit power, M_(PSFCH) is a bandwidth ofthe PSFCH resource assignment expressed in number of resource blocks,and α_(c) and P_(O_PSFCH_c) are an uplink pathloss compensation factorand a power value, respectively, that are provided by higher layers.PL_(c) is the estimated pathloss between the gNB and the transmitter UE.α_(sl) and P_(O_PSFCH_sl) are a sidelink pathloss compensation factorand a power setting that are provided by higher layers. PL_(sl) is thepathloss between the transmitter UE and the receiver UE. μ is related tothe subcarrier spacing where μ=0, 1, 2, 3 corresponds to subcarrierspacing of 15, 30, 60 and 120 kHz respectively.

The receiver UE performs power control without being able to account forthe combined power of the PSFCH receptions from multiple receiver UEs atthe transmitter UE. Accordingly, embodiments provide mechanisms forcontrolling a received power of a PSFCH transmission that occurs onlywhen a receiver UE indicates a NACK value for a TB reception and uses aresource that can be common for PSFCH transmissions from multiple UEs.

In one embodiment, at least one of the α_(sl) or P_(O_PSFCH_sl) can beconfigured to a receiver UE by a transmitter UE. The configuration canbe performed by PC5 higher layer signaling and stored in the memory 260of the transmitter UE. When a large number of receiver UEs transmitrespective PSFCHs to convey respective NACK values in a same PSFCHresource, the transmitter UE can measure the received signal strength.When the received signal strength is large, the transmitter UE canconfigure smaller values for the α_(sl) and/or P_(O_PSFCH_sl) parametersto the receiver UEs. When the received signal strength is small, thetransmitter UE can configure larger values for the α_(sl) and/orP_(O_PSFCH_sl) parameters to the receiver UEs.

For example, an index to the entry of the α_(sl) and/or P_(O_PSFCH_sl)configuration table can be used in the signaling to indicatecorresponding α_(sl) and/or P_(O_PSFCH_sl) values. Table 1 is an exampleof indexes that can be signaled by a transmitter UE to receiver UEs andcorrespond to α_(sl) and/or P_(O_PSFCH_sl) values. The index shown inTable 1 can be stored in the memory 260.

TABLE 1 Index α_(sl) P_(O) _(—) _(PSFCH) _(—) _(sl) 0 xx xx 1 xx xx 2 xxxx . . . . . . . . .

In another embodiment, the α_(sl) and/or P_(O_PSFCH_sl) can be indicatedin a SCI format in a PSCCH transmission by the transmitter UE. When alarge number of receiver UEs transmit PSFCH in a same resource to conveya NACK value to the transmitter UE, the transmitter UE can measure thereceived signal strength. When the received signal strength is large,the transmitter UE can indicate in a SCI format a smaller value for theα_(sl) and/or P_(O_PSFCH_sl) parameters to the receiver UEs byindicating a corresponding index in a predetermined/preconfigured Table.When the received signal strength is small, the transmitter UE canindicate in the SCI format a larger value for the α_(sl) and/orP_(O_PSFCH_sl) parameters to the receiver UEs.

For example, an index to the entry of the α_(sl) and/or P_(O_PSFCH_sl)configuration table can be used to indicate corresponding α_(sl) and/orP_(O_PSFCH_sl) values. Table 2 is an example of an index correspondingto α_(sl) and/or P_(O_PSFCH_sl). The index shown in Table 2 can bestored in the memory 260.

TABLE 2 Index α_(sl) P_(O) _(—) _(PSFCH) _(—) _(sl) 0 xx xx 1 xx xx 2 xxxx . . . . . . . . .

In another embodiment, at least one of the α_(sl) or P_(O_PSFCH_sl) fora receiver UE is separately configured from the power control parametersof PSCCH/PSSCH channels. The α_(sl) and/or P_(O_PSFCH_sl) for a receiverUE is separately configured for HARQ-ACK information reporting option 2in groupcast. For example, Table 3 shows power control parameters ofPSCCH/PSSCH and PSFCH according to various groupcast HARQ-ACKinformation reporting options. Table 3 can be stored in the memory 260.

TABLE 3 Physical layer channels groupcast HARQ options Index α_(sl)P_(O) _(—) _(sl) PSCCH/PSSCH N/A 0 xx xx 1 xx xx 2 xx xx . . . . . . . .. PSFCH Option 1 0 xx xx 1 xx xx . . . . . . . . . PSFCH Option 2 0 xxxx 1 xx xx . . . . . . . . .

As described herein, various embodiments of the present disclosureprovide power control for sidelink transmissions. For example, the UEtransmit power for a sidelink transmission can be determined based onEquation 2, provided below.P _(SL)=min(P _(CMAX) ,P _(O_c)+10 log₁₀(2^(μ) ·M)+α_(c) ·PL _(c) ,P_(O_sl)+10 log₁₀(2^(μ) ·M)+α_(sl) ·PL _(sl))[dBm]  Equation 2

In Equation 2, P_(SL) is a UE transmit power for the sidelinktransmission, P_(CMAX) is a maximum (pre)configured UE power, and M is abandwidth of the sidelink resource assignment expressed in number ofresource blocks. α_(c) and P_(O_c) are an uplink pathloss scaling factorand a power setting and are provided by higher layers. PL_(c) is anestimated pathloss between the gNB and the transmitter UE. α_(sl) andP_(O_sl) are a sidelink pathloss scaling factor and a power setting andare provided by higher layers. PL_(sl) is the pathloss between thetransmitter UE and the receiver UE. μ is related to the subcarrierspacing where μ=0, 1, 2, 3 corresponds to subcarrier spacing of 15, 30,60, and 120 kHz respectively.

When a transmission power of a UE, such as the UE 116, considers boththe Uu pathloss between the gNB 102 and the UE 116 and the sidelinkpathloss between the UE 116 and the receiver UE(s), if the Uu path lossis lower than sidelink pathloss, the power is bounded by the powercalculated based on the Uu pathloss. Then, the transmission power can belower than required for the sidelink and cause decoding errors.Accordingly, embodiments of the present disclosure provide a refinedmechanism for calculating a sidelink transmission power.

For example, α_(sl) and P_(O_sl), α_(c) and P_(O_c) can be configuredbased on the zone where a UE is located. In a zone near the gNB, α_(c)and P_(O_c) can be configured to have larger values. In a zone far fromthe gNB, α_(c), and P_(O_c) can be configured to have smaller values.

For each resource pool, a UE can be provided separate configurations forthe α_(sl), and P_(O_sl), α_(c), and P_(O_c) values. The configurationscan also be separate per zone ID. The power control parameters can beconfigured as shown in Table 4 where each zone ID corresponds to a setof power control parameters α_(c) and P_(O_c).

TABLE 4 Zone ID α_(c) P_(O) _(—) _(c) 0 xx xx 1 xx xx 2 xx xx . . . . .. . . .

The configuration of the power control parameters can be separate amongresource pools as shown in Table 5 below.

TABLE 5 Resource Pool ID Zone ID α_(c) P_(O) _(—) _(c) 0 0 xx xx 1 xx xx2 xx xx . . . . . . . . . 1 0 xx xx 1 xx xx . . . . . . . . . . . . . .. . . . . . .

As described herein, various embodiments of the present disclosureprovide mechanisms for CSI-RS power control. In one embodiment, areceiver UE can calculate a pathloss based on a CSI-RS transmission froma transmitter UE. A transmission power of CSI-RS can be fixed, orderived from a PSSCH transmission power, or configured by higher layers,or indicated by a SCI format for example by indicating a table entry fora CSI-RS transmission power or by indicating an offset relative to thePSSCH transmission power. In another embodiment, the CSI-RS transmissionpower is always same as that the PSSCH transmission power in the PSSCHresource where CSI-RS is transmitted.

As described herein, various embodiments of the present disclosureprovide mechanisms for a CSI-RS transmission. For example, periodic orsemi-persistent CSI-RS transmission can be supported when a periodic orsemi-persistent resource is allocated for a UE. In this case, a SCIformat can indicate whether a periodic or semi-persistent CSI-RS istransmitted in the allocated periodic or semi-persistent resource. Whenthere is no data in a periodic PSCCH/PSSCH periodic or semi-persistentresource, only CSI-RS is transmitted in the PSCCH/PSSCH periodic orsemi-persistent resource.

In one embodiment, when a SCI format indicates the periodic orsemi-persistent PSCCH/PSSCH resource allocation, the SCI format can alsoindicate that CSI-RS is transmitted periodically or semi-persistently.In various embodiments, the indication can be in the first stage SCIformat or in the second stage SCI format when a 2-stage SCI format isused.

As described herein, various embodiments of the present disclosureprovide mechanisms for CSI reporting. For example, periodic orsemi-persistent CSI reporting can be supported when a periodic orsemi-persistent resource is allocated for a UE. In this case, a SCIformat can indicate whether periodic or semi-persistent CSI reporting istransmitted in the allocated periodic or semi-persistent resource. Whenthere is no data in a periodic PSCCH/PSSCH periodic or semi-persistentresource, CSI reporting alone is transmitted in the PSCCH/PSSCH periodicor semi-persistent resource.

In one embodiment, when a SCI format indicates the periodic orsemi-persistent PSCCH/PSSCH resource allocation, the SCI format canindicate the CSI reporting is transmitted periodically orsemi-persistently. In various embodiments, the indication can be in thefirst stage SCI format or in the second stage SCI format when a 2-stageSCI format is used.

As described herein, various embodiments of the present disclosureprovide mechanisms for reservation signal power control. A reservationsignal can be a broadcast signal. The power of the reservation signalcan be calculated by the open-loop power control based on DL pathlosswhen DL pathloss is available. The configuration of power controlparameters for a reservation signal can be separate from other channelssuch as PSCCH/PSSCH or PSFCH.

As described herein, various embodiments of the present disclosureprovide a maximum UE transmit power. For example, P_(CMAX) can refer tothe maximum (pre)configured UE power in the power control formula. Insome embodiments, multiple maximum UE transmit powers P_(CMAX) can be(pre)configured for different conditions. P_(CMAX) can be determinedbased on one or more of a type of service, priority of service, orchannel status. A UE, such as the UE 116, can use a configured P_(CMAX)depending upon different conditions. For example, in a congestedsituation, the UE 116 can use a lower P_(CMAX). For broadcast services,the UE 116 can use a higher P_(CMAX). For a higher priority service, theUE 116 can use a higher P_(CMAX).

For example, for the UE 116, P_(CMAX) can be configured based on Table 6below. The contents of Table 6 can be stored in the memory 260.

TABLE 6 Index P_(CMAX) Type of Service CBR Priority 0 xx xx xx xx 1 xxxx xx xx 2 xx xx xx xx . . . . . . . . . . . . . . .

As described herein, various embodiments of the present disclosureprovide mechanisms for power sharing between uplink and sidelinktransmissions. For example, power sharing between uplink and sidelinktransmissions can be applied for simultaneous transmissions for bothuplink and sidelink. The transmission power for uplink is calculated asa linear value of P _(UL) and the transmission power for sidelink iscalculated as a linear value of P _(SL). P _(MAX) is a linear value ofthe configured, or preconfigured, maximum UE transmit power. In eachmethod, the UE 116 can additionally consider congestion (CBR) todetermine whether to drop a packet or use reduced power fortransmission.

There can be several ways for the UE 116 to determine a transmit poweron the uplink and the sidelink. For example, if P _(UL)+P _(SL)≤P_(MAX), P _(UL) and P _(SL) are used for the respective uplink andsidelink UE transmit power. If P _(UL)+P _(SL)>P _(MAX), the UE 116 canreduce the transmission power of P _(UL) for sidelink so that P _(UL)+P_(SL)≤P _(MAX). If P _(UL)+P _(SL)>P _(MAX), the UE 116 can reduce thetransmission power of P _(UL) for uplink so that P _(UL)+P _(SL)≤P_(MAX) Further, if the reduced sidelink transmission power is below athreshold value P _(SL_TH), the UE 116 can drop the sidelinktransmission and trigger a resource selection, or reselection,procedure.

If P _(UL)+P _(SL)>P _(MAX), the UE 116 reduces the transmission powerof P _(SL) for sidelink so that P _(UL)+P _(SL)≤P _(MAX). Further, ifthe reduced sidelink transmission power is below a threshold value P_(SL_TH) and sidelink transmission priority is below a priority valueTH_(pri), the UE 116 can drop the sidelink transmission and triggerresource (re)selection procedure. If the reduced sidelink transmissionpower is below a threshold value P _(SL_TH) and sidelink transmissionpriority is above or equal to a priority value TH_(pri), the UE 116transmits with the reduced transmission power of P _(SL).

If P _(UL)+P _(SL)>P _(MAX) and the sidelink transmission priority isabove or equal to a priority value TH_(pri), the UE 116 reduces thetransmission power of P _(UL) for uplink so that P _(UL)+P _(SL)≤P_(MAX). If the sidelink transmission priority is below a priority valueTH_(pri), the UE 116 reduces the transmission power of P _(SL) forsidelink so that P _(UL)+P _(SL)≤P _(MAX).

If P _(UL)+P _(SL)>P _(MAX) and the sidelink transmission priority isabove or equal to a priority value TH_(pri), the UE 116 reduces thetransmission power of P _(UL) for uplink so that P _(UL)+P _(SL)≤P_(MAX). If the sidelink transmission priority is below a priority valueTH_(pri), the UE 116 reduces the transmission power of P _(sL) forsidelink so that P _(UL)+P _(SL)≤P _(MAX). If the reduced sidelinktransmission power is below a threshold value P _(SL_TH), the UE 116 candrop the sidelink transmission and trigger a resource selection, orreselection, procedure.

If P _(UL)+P _(SL)>P _(MAX) and the sidelink transmission priority isabove or equal to a priority value TH_(pri), the UE 116 reduces thetransmission power of P _(UL) for uplink so that P _(UL)+P _(SL)≤P_(MAX). If the sidelink transmission priority is below a priority valueTH_(pri), the UE 116 reduces the transmission power of P _(sL) forsidelink so that P _(UL)+P _(SL)≤P _(MAX). If the reduced sidelinktransmission power is below a threshold value P _(SL_TH) and sidelinktransmission priority is below a priority value TH_(pri2), the UE 116can drop the sidelink transmission and trigger resource selection, orreselection, procedure. If the reduced sidelink transmission power isbelow a threshold value P _(SL_TH) and sidelink transmission priority isabove or equal to a priority value TH_(pri2), the UE 116 transmits withthe reduced transmission power of P _(SL).

If P _(UL)+P _(SL)>P _(MAX), the UE 116 can scale the transmission powerof P _(UL) and P _(SL) for uplink and sidelink so that P _(UL)+P _(SL)≤P_(MAX). If the reduced sidelink transmission power is below a thresholdvalue P _(SL_TH), the UE 116 can drop the sidelink transmission andtrigger resource (re)selection procedure.

If P _(UL)+P _(SL)>P _(MAX), the UE 116 scales the transmission power ofP _(UL) and P _(SL) for uplink and sidelink so that P _(UL)+P _(SL)≤P_(MAX). If the reduced sidelink transmission power is below a thresholdvalue P _(SL_TH) and sidelink transmission priority is below a priorityvalue TH_(pri), the UE 116 can drop the sidelink transmission andtrigger resource selection, or reselection, procedure. If the reducedsidelink transmission power is below a threshold value P _(SL_TH) andsidelink transmission priority is above or equal to a priority valueTH_(pri), the UE 116 transmits with the reduced transmission power of P_(SL).

As described herein, various embodiments of the present disclosureprovide power sharing between Mode 1 and Mode 2. When there is asimultaneous transmission for both Mode 1 and Mode 2 for a particular UE116, power between Mode 1 and Mode 2 is shared. The transmission powerfor Mode 1 is calculated as a linear value P _(M1) of and thetransmission power for sidelink is calculated as a linear value of P_(M2). P _(MAX) is a linear value of the configured or preconfiguredmaximum UE transmit power. In each method, the UE 116 can additionallyconsider congestion (CBR) to determine whether to drop a packet or usereduced power for transmission.

If P _(M1)+P _(M2)≤P _(MAX), P _(M1) and P _(M2) are used for therespective uplink and sidelink UE transmit power. If P _(M1)+P _(M2)>P_(MAX), the UE 116 can reduce the transmission power of for sidelink sothat P _(M1)+P _(M2)≤P _(MAX). If P _(M1)+P _(M2)>P _(MAX), the UE 116can reduce the transmission power of P _(M2) for sidelink so that P_(M1)+P _(M2)≤P _(MAX). If P _(M1)+P _(M2)>P _(MAX), when Mode 1transmission has a higher priority than Mode 2 transmission, the UE 116reduces the transmission power of P _(M2) for sidelink so that P _(M1)+P_(M2)≤P _(MAX). When Mode 2 transmission has a higher priority than Mode1 transmission, the UE 116 reduces the transmission power of P _(M1) forsidelink so that P _(M1)+P _(M2)≤P _(MAX).

If P _(M1)+P _(M2)>P _(MAX), the UE 116 reduces the transmission powerof P _(M1) for sidelink so that P _(M1)+P _(M2)≤P _(MAX). If the reducedsidelink transmission power P _(M1) is below a threshold value P_(sL_TH), the UE 116 can drop the sidelink transmission and triggerresource selection, or reselection, procedure.

If P _(M1)+P _(M2)>P _(MAX), the UE 116 reduces the transmission powerof P _(M2) for sidelink so that P _(M1)+P _(M2)≤P _(MAX). If the reducedsidelink transmission power P _(M2) is below a threshold value P_(SL_TH), the UE 116 can drop the sidelink transmission and triggerresource selection, or reselection, procedure.

If P _(M1)+P _(M2)>P _(MAX), when Mode 1 transmission has a higherpriority than Mode 2 transmission, the UE 116 reduces the transmissionpower of P _(M2) for sidelink so that P _(M1)+P _(M2)≤P _(MAX). If thereduced sidelink transmission power P _(M2) is below a threshold value P_(SL_TH2), the UE 116 can drop the sidelink transmission and triggerresource (re)selection procedure. When Mode 2 transmission has a higherpriority than Mode 1 transmission, the UE 116 reduces the transmissionpower of P _(M1) for sidelink so that P _(M1)+P _(M2)≤P _(MAX). If thereduced sidelink transmission power P _(M1), is below a threshold valueP _(SL_TH1), the UE 116 can drop the sidelink transmission and triggerresource selection, or reselection, procedure.

If P _(M1)+P _(M2)≤P _(MAX), the UE 116 scales the transmission power ofP _(M1) and P _(M2) for sidelink so that P _(M1)+P _(M2)≤P _(MAX). If P_(M1)+P _(M2)>P _(MAX) the UE 116 scales the transmission power of P_(M1), and P _(M2) for sidelink so that P _(UL)+P _(SL)≤P _(MAX) If thereduced sidelink transmission power P _(M1) is below a threshold value P_(SL_TH), the UE 116 can drop the sidelink transmission and triggerresource selection, or reselection, procedure. If the reduced sidelinktransmission power P _(M2) is below a threshold value P _(SL_TH2), theUE 116 can drop the sidelink transmission and trigger resourceselection, or reselection, procedure.

If P _(M1)+P _(M2)≤P _(MAX), the UE 116 scales the transmission power ofP _(M1) and P _(M2) for sidelink so that P _(UL)+P _(SL)≤P _(MAX). Ifthe reduced sidelink transmission power P _(M1) is below a thresholdvalue P _(SL_TH1) and sidelink transmission priority is below a priorityvalue TH_(pri1), the UE 116 can drop the sidelink transmission andtrigger resource selection, or reselection, procedure. If the reducedsidelink transmission power P _(M2) is below a threshold value P_(SL_TH2) and sidelink transmission priority is below a priority valueTH_(pri2), the UE 116 can drop the sidelink transmission and triggerresource selection, or reselection, procedure.

Various embodiments of the present disclosure provide mechanisms for NRsidelink power saving operation. As described herein, RRC can controlconfiguration of DRX operation. The DRX operation can be controlled byconfiguring timers. In particular, drx-onDurationTimer is the timer forthe duration at the beginning of a DRX Cycle, drx-SlotOffset is thetimer for the delay in slots before starting the drx-onDurationTimer,and drx-InactivityTimer is the timer for the duration after the PDCCHoccasion in which a PDCCH indicates an initial UL or DL user datatransmission for the MAC entity. drx-RetransmissionTimerDL (per DL HARQprocess) is the timer for the maximum duration until a DL retransmissionis received, drx-RetransmissionTimerUL (per UL HARQ process) is thetimer for the maximum duration until a grant for UL retransmission isreceived, and drx-LongCycle is the timer for the Long DRX cycle.drx-ShortCycle can be an option timer for the Short DRX cycle,drx-ShortCycleTimer can be an optional timer for the duration the UEfollows for the Short DRX cycle, drx-HARQ-RTT-TimerDL (per DL HARQprocess) can be the timer for the minimum duration before a DLassignment for HARQ retransmission is expected by the MAC entity, anddrx-HARQ-RTT-TimerUL (per UL HARQ process) is the timer for the minimumduration before a UL HARQ retransmission grant is expected by the MACentity.

When a DRX cycle is configured, the Active Time includes time whiledrx-onDurationTimer or drx-InactivityTimer or drx-RetransmissionTimerDLor drx-RetransmissionTimerUL or ra-ContentionResolutionTimer is running,a Scheduling Request is sent on PUCCH and is pending, or a PDCCHindicating a new transmission addressed to the C-RNTI of the MAC entityhas not been received after successful reception of a Random AccessResponse for the preamble not selected by the MAC entity.

When the DRX is configured, the MAC entity can follow the followingprocedure.

-   -   1> if a drx-HARQ-RTT-TimerDL expires:        -   2> if the data of the corresponding HARQ process was not            successfully decoded:            -   3> start the drx-RetransmissionTimerDL for the                corresponding HARQ process.    -   1> if an drx-HARQ-RTT-TimerUL expires:        -   2> start the drx-RetransmissionTimerUL for the corresponding            HARQ process.    -   1> if a DRX Command MAC CE or a Long DRX Command MAC CE is        received:        -   2> stop drx-onDurationTimer;        -   2> stop drx-InactivityTimer.    -   1> if drx-InactivityTimer expires or a DRX Command MAC CE is        received:        -   2> if the Short DRX cycle is configured:            -   3> start or restart drx-ShortCycleTimer;            -   3> use the Short DRX Cycle.        -   2> else:            -   3> use the Long DRX cycle.    -   1> if drx-ShortCycleTimer expires:        -   2> use the Long DRX cycle.    -   1> if a Long DRX Command MAC CE is received:        -   2> stop drx-ShortCycleTimer;        -   2> use the Long DRX cycle.    -   1> if the Short DRX Cycle is used, and [(SFN*10)+subframe        number] modulo (drx-ShortCycle)=(drx-StartOffset) modulo        (drx-ShortCycle); or    -   1> if the Long DRX Cycle is used, and [(SFN*10)+subframe number]        modulo (drx-LongCycle)=drx-StartOffset:        -   2> if drx-SlotOffset is configured:            -   3> start drx-onDurationTimer after drx-SlotOffset.        -   2> else:            -   3> start drx-onDurationTimer.    -   1> if the MAC entity is in Active Time:        -   2> monitor the PDCCH;        -   2> if the PDCCH indicates a DL transmission or if a DL            assignment has been configured:            -   3> start the drx-HARQ-RTT-TimerDL for the corresponding                HARQ process immediately after the corresponding PUCCH                transmission;            -   3> stop the drx-RetransmissionTimerDL for the                corresponding HARQ process.        -   2> if the PDCCH indicates a UL transmission or if a UL grant            has been configured:            -   3> start the drx-HARQ-RTT-TimerUL for the corresponding                HARQ process immediately after the first repetition of                the corresponding PUSCH transmission;            -   3> stop the drx-RetransmissionTimerUL for the                corresponding HARQ process.        -   2> if the PDCCH indicates a new transmission (DL or UL):            -   3> start or restart drx-InactivityTimer.    -   1> else (i.e. not part of the Active Time):        -   2> not report CQI/PMI/RI on PUCCH.

As described herein, V2X includes communications between Pedestrian UEsand Vehicular UEs, (V2P). Whereas a vehicular UE, such as the UE 118, isassumed to be attached the vehicle's power supply, and thus to have noparticular battery life concerns, the situation is different for a P-UE.A P-UE could be, for example, a conventional smartphone running suitableapplications or a specialized device attached to a pedestrians clothing.In either case, battery life is a consideration so that the device canprovide the V2P services for a reasonable length of time without need ofre-charging and without imposing such battery drain that V2Papplications could become unattractive. In some embodiments, the P-UEcan be the UE 116 described herein.

A UE can perform sensing continuously in a 1000 ms historical window,implying an amount of ongoing power consumption due to the sensingprocedure. A P-UE may not support sidelink reception so the P-UE is onlybroadcasting packets relating to its own location and direction. Thistype of P-UE can be allowed to select transmission resources randomly,with no sensing procedure. For a P-UE that does support sidelinkreception, the P-UE can be configured, or preconfigured, to performpartial sensing. In partial sensing, the P-UE monitors only a subset ofthe subframes/slots in the typically 1000 ms sensing window. The UEimplementation can choose a number of subframes/slots to monitor bytrading off reliability of transmissions and power savings, subject tomonitoring a configured or preconfigured minimum number ofsubframes/slots. A pre-configuration can also set how far into the pastthe sensing window extends and require that the UE performs partialsensing in a number of truncated sensing windows.

Accordingly, various embodiments of the present disclosure providemechanisms for sidelink power saving operation and an enhanced resourceallocation for power saving UEs. The power saving operation can apply toUEs, such as pedestrian UEs, that communicate in sidelink and have arequirement on lower power consumption. In particular, the presentdisclosure provides support of DRX operation, a power saving signal orchannel, support of DRX operations with a reservation signal, andresource allocation.

Sidelink DRX parameters are configured by sidelink higher layers forout-of-coverage or in-coverage Mode 2 UEs. For in-coverage Mode 1 UEs,DRX parameters can be configured by Uu and/or sidelink higher layers.The Uu link and the sidelink for a UE can be configured to use a same orseparate set of DRX parameters. Sidelink DRX parameters are configuredby Uu higher layers for in-coverage Mode 1 UEs. The configuration can beprovided to both the transmitter UE and the power saving/receiver UE intheir respective Uu links when RRC is established with the gNB, or theconfiguration can be provided only to the power saving/receiver UE inthe Uu link, while the configuration for the transmitter UE is providedin the sidelink by the power saving/receiver UE when PC5-RRC isestablished.

A power saving signal or channel can be configured by higher layers andtransmitted by a transmitter UE for triggering a receiver UE whether ornot to monitor a subsequent On Duration time in a next DRX cycle (or anumber of next DRX cycles). The configuration for the sidelink powersaving signal or channel can be provided by PC5 higher layers when aunicast connection is established among the UEs. For out-of-coverage UEsor Mode 2 UEs, the power saving signal or channel can be independentfrom a Uu link power saving signal or channel and can be provided by aSCI format in a PSCCH or by a MAC CE or RRC signaling in a PSSCH. Forin-coverage Mode 1 UEs, a DCI format in a PDCCH can provide power savinginformation for both Uu and sidelink. When a DCI format in a PDCCHindicates to the UE to wake up for sidelink, the UE monitors PSCCH inthe sidelink according to the sidelink DRX cycle configuration. When aDCI format in a PDCCH indicates to the UE to wake up for Uu link, the UEmonitors PDCCH in Uu link according to the Uu link DRX cycleconfiguration. When a DCI format in a PDCCH indicates to the UE to wakeup for both Uu link and sidelink, the UE monitors both PDCCH in Uu linkaccording to the Uu link DRX cycle and PSCCH in sidelink according tothe sidelink DRX cycle.

For in-coverage Mode 1 UEs, a DCI format provided by a PDCCH canindicate to a UE to monitor PSCCH in the sidelink while a same ordifferent DCI format provided by a PDCCH can indicate to the UE tomonitor PDCCH in the Uu link. For an in-coverage Mode 1 UE, differentpower saving signals or channels for sidelink and Uu link can be used toindicate to the UE to monitor PSCCH and to monitor PDCCH, respectively,in a next respective DRX cycle. For in-coverage Mode 1 UEs, theconfiguration for an in-coverage sidelink power saving signal or channelcan be provided to a receiver UE by Uu higher layers after the UEestablishes RRC connection. The configuration can be provided to boththe transmitter UE and the receiver UE in their respective Uu links, orthe configuration for sidelink power saving signal or channel can beprovided only to the receiver UE in the Uu link, while the configurationfor sidelink power saving signal or channel for the transmitter UE canbe provided in the sidelink by the receiver UE after PC5-RRC isestablished.

A reservation signal can also be used as a sidelink power saving signalor channel to indicate to a UE to wake up for monitoring PSCCH in the OnDuration time of a next DRX cycle.

For resource allocation, when the DRX procedure is used in sidelink, thepartial set of slots used for sensing and measurements can be selectedfrom slots that are configured to be active in each DRX cycle within asensing window, such as a drx-onDurationTimer.

As described herein, various embodiments of the present disclosureprovide mechanisms to support DRX operation in sidelink. The DRXmechanism can reduce power consumption for UEs in unicast. Inparticular, a UE, such as the UE 116, wakes and receives or transmitssignals only during a small percentage of time in a DRX cycle. Duringthe remainder of the DRX cycle, the UE 116 can enter a sleeping mode ifthere is no data to transmit or receive. As described herein, any UE111-118 that can communicate with a power saving UE can be a transmitterUE.

In some embodiments, such as for a Mode 2 UE that is either out ofcoverage or in coverage, the DRX parameters can be configured by higherlayers of a sidelink after the UE establishes unicast RRC connection.The DRX parameters that can be configured include various timers. Forexample, drx-onDurationTimer is a timer for the On Duration at thebeginning of a DRX Cycle, drx-SlotOffset is a timer for the delay inslots before starting the drx-onDurationTimer, and drx-InactivityTimerSLis a timer for the duration after the PSCCH occasion in which a PSCCHindicates an initial sidelink PSSCH user data transmission for the MACentity or there is an initial PSSCH user data transmitted by the UE 116.drx-RetransmissionTimerSL (per Sidelink HARQ process, retransmission isfrom the transmitter UE to the power saving UE) is a timer for themaximum duration until a sidelink retransmission is received, whenHARQ-ACK information reporting is enabled. drx-RetransmissionTimerSL isdisabled when HARQ-ACK information reporting is disabled.

drx-RetransmissionTimerSL2 (per Sidelink HARQ process, retransmission isfrom the power saving UE to the transmitter UE) is a timer for themaximum duration until a sidelink retransmission is sent, when HARQ-ACKinformation reporting is enabled. drx-RetransmissionTimerSL2 is disabledwhen HARQ-ACK information reporting is disabled.drx-LongCycleStartOffset is a timer for the Long DRX cycle drx-LongCycleand for drx-StartOffset, that defines the subframe/slot where the Longand Short DRX Cycle starts. drx-ShortCycle is an optional timer for theShort DRX cycle. drx-ShortCycleTimer is an optional timer for theduration the UE shall follow the Short DRX cycle. drx-HARQ-RTT-TimerSL(per SL HARQ process, retransmission is from the transmitter UE to thepower saving UE) is a timer for the minimum duration before a sidelinkassignment for HARQ retransmission is expected by the MAC entity.drx-HARQ-RTT-TimerSL2 (per SL HARQ process, retransmission is from thepower saving UE to the transmitter UE) is a timer for a minimum durationbefore sidelink HARQ-ACK information for HARQ retransmission is expectedby the MAC entity. In some embodiments, different UEs 111-118 can beconfigured with different drx-StartOffset values for UE resourceallocation to avoid resource conflict.

In some embodiments, for in-coverage Mode 1 UEs, the DRX parameters canbe configured by Uu and/or sidelink higher layers. The Uu link and thesidelink for a UE, such as the UE 116, can be configured to use a sameset of DRX parameters. A DRX parameter can have different functionalitydepending on whether or not the DRX parameter is for the sidelink or forthe Uu link because sidelink DRX is considered for in-coverage UEs. Forexample, drx-RetransmissionTimerDL can be interpreted as per DL HARQprocess where retransmission is from the gNB 102 to the UE 116, or perSL HARQ process where retransmission is from the transmitter UE to thepower saving UE. The DRX parameters can include various timers. Forexample, drx-onDurationTimer is a timer for the On Duration at thebeginning of a DRX Cycle, drx-SlotOffset is a timer for the delay inslots before starting the drx-onDurationTimer, and drx-InactivityTimeris a timer for a duration after a PDCCH monitoring occasion where a UEreceives a PDCCH with a DCI format that indicates an initial TBtransmission in a PDSCH or a PUSCH for the MAC entity or after a PSCCHmonitoring occasion where a UE receives a PSCCH with a SCI format thatindicates an initial TB transmission in a PSSCH for the MAC entity orthere is an initial TB transmission in a PSSCH by the UE 116.

drx-RetransmissionTimerDL (per DL HARQ process or per SL HARQ processwhere retransmission is from the transmitter UE to the power saving UE)is a timer for a maximum duration until a DL retransmission for a TB isreceived or a maximum duration until a sidelink retransmission for a TBis received, when HARQ-ACK information reporting is enabled.drx-RetransmissionTimerDL is disabled for sidelink when HARQ-ACKinformation reporting is disabled. drx-RetransmissionTimerUL (per ULHARQ process or per SL HARQ process where retransmission is from thepower saving UE to the transmitter UE) is a timer for a maximum durationuntil a grant for UL retransmission is received or a maximum durationuntil a sidelink retransmission is sent, when HARQ-ACK informationreporting is enabled. drx-RetransmissionTimerUL is disabled for sidelinkwhen HARQ-ACK information reporting is disabled.

drx-LongCycleStartOffset is a timer for the Long DRX cycle drx-LongCycleand drx-StartOffset, that defines a subframe/slot where the Long andShort DRX Cycle starts. drx-ShortCycle is an optional timer for theShort DRX cycle. drx-ShortCycleTimer is an optional timer for a durationthe UE follows the Short DRX cycle. drx-HARQ-RTT-TimerDL (per DL HARQprocess or per sidelink HARQ process where retransmission is from thetransmitter UE to the power saving UE) is a timer for the minimumduration before a DL assignment for HARQ retransmission is expected bythe MAC entity or a minimum duration before a sidelink assignment forHARQ retransmission is expected by the MAC entity. drx-HARQ-RTT-TimerUL(per UL HARQ process or sidelink HARQ process where retransmission isfrom the power saving UE to the transmitter UE) is a timer for a minimumduration before a UL HARQ retransmission grant is expected by the MACentity or a minimum duration before a sidelink HARQ-ACK information forHARQ retransmission is expected by the MAC entity.

As described herein, for in-coverage Mode 1 UEs, the DRX parameters canbe configured by Uu and/or sidelink higher layers. The Uu link and thesidelink for a UE can be configured to use a separate set of DRXparameters, in addition to common DRX parameters for Uu link, such asdrx-onDurationTimer, drx-SlotOffset, drx-LongCycleStartOffset,drx-ShortCycle, drx-ShortCycleTimer. The configured DRX parameters caninclude various timers.

For example, drx-onDurationTimer is a timer for the On Duration at thebeginning of a DRX Cycle. drx-onDurationTimer can be common for Uu linkand sidelink. drx-SlotOffset is a timer for a delay in slots beforestarting the drx-onDurationTimer. drx-SlotOffset can be common for Uulink and sidelink. drx-InactivityTimer is a timer for a duration after aPDCCH monitoring occasion where a DCI format in a PDCCH indicates aninitial transmission for a TB in a PUSCH or PDSCH for the MAC entity.drx-InactivityTimerSL is a timer for a duration after a PSCCH monitoringoccasion where a SCI format in a PSCCH indicates an initial TBtransmission in a PSSCH for the MAC entity or there is an initial TBtransmission in a PSSCH by the UE 116.

drx-RetransmissionTimerDL (per DL HARQ process) is a timer for a maximumduration until a retransmission for a TB in the DL is received.drx-RetransmissionTimerUL (per UL HARQ process) is a timer for a maximumduration until a grant for a TB retransmission in the UL is received.drx-RetransmissionTimerSL (per Sidelink HARQ process whereretransmission is from the transmitter UE to the power saving UE) is atimer for a maximum duration until a sidelink retransmission for a TB isreceived, when HARQ-ACK information reporting is enabled.drx-RetransmissionTimerSL can be disabled when HARQ-ACK informationreporting is disabled. drx-RetransmissionTimerSL2 (per Sidelink HARQprocess where retransmission is from the power saving UE to thetransmitter UE) is a timer for a maximum duration until a sidelinkretransmission is sent, when HARQ-ACK information reporting is enabled.drx-RetransmissionTimerSL2 can be disabled when HARQ-ACK informationreporting is disabled. drx-LongCycleStartOffset is a timer for the LongDRX cycle drx-LongCycle and drx-StartOffset that defines a slot/subframewhere the Long and Short DRX Cycle starts. drx-LongCycleStartOffset canbe common for Uu link and sidelink. drx-ShortCycle is an optional timerfor the Short DRX cycle and can be common for Uu link and sidelink.drx-ShortCycleTimer is an optional timer for a duration a UE follows theShort DRX cycle and can be common for Uu link and sidelink.

drx-HARQ-RTT-TimerDL (per DL HARQ process) is a timer for a minimumduration before a DL assignment for HARQ retransmission is received bythe MAC entity. drx-HARQ-RTT-TimerUL (per UL HARQ process) is a timerfor a minimum duration before a UL HARQ retransmission grant is receivedby the MAC entity. drx-HARQ-RTT-TimerSL (per SL HARQ process whereretransmission is from the transmitter UE to the power saving UE) is atimer for a minimum duration before a sidelink assignment for HARQretransmission is received by the MAC entity. drx-HARQ-RTT-TimerSL2 (persidelink HARQ process where retransmission is from the power saving UEto the transmitter UE) is a timer for a minimum duration before asidelink HARQ-ACK information for HARQ retransmission is received by theMAC entity.

In some embodiments, there can be multiple sidelink connections betweena UE, such as the UE 116, and other UEs, such as the UE 118. In theseembodiments, the UE 116 can use a same set of DRX parameters for allsidelink connections with the other UEs 118. If the UE 116 operates inMode 2, the configuration can be provided to other UEs 118 in sidelinkby the UE 116.

In embodiments where UEs are in a groupcast or broadcast, a DRXmechanism can reduce power consumption. Since all UEs in a groupcast orbroadcast are simultaneously active for receiving data from another UE,the DRX cycle for the UEs can be same. For example, the same timer suchas drx-onDurationTimer, drx-SlotOffset, drx-LongCycleStartOffset,drx-ShortCycle, and drx-ShortCycleTimer can be used. For Mode 2 UEs inthe group, the configuration can be provided to UEs in the group insidelink by one of the UEs in the group. Further, the information can beprovided by a groupcast or broadcast PSSCH.

In embodiments where UEs are in-coverage Mode 1 UEs, a configuration forDRX parameters can be provided to a power saving UE by Uu higher layersafter the UE establishes RRC connection with a gNB. For example, theconfiguration can be provided to both a transmitter UE 118 and a powersaving UE 116 in their respective Uu links. As another example, theconfiguration can be provided only to the power saving UE 116 in the Uulink while the configuration for the transmitter UE 118 can be providedin the sidelink by the power saving UE 116 after PC5-RRC is established.The configuration procedure can also be applied to UEs in groupcast orbroadcast PSSCH receptions.

Various embodiments of the present disclosure provide mechanisms for apower saving signal or channel. For example, to reduce powerconsumption, as in a NR Uu link, a power saving signal or channel can beconfigured by higher layers and transmitted by one or more transmitterUEs to indicate, to a UE, whether or not to monitor PSCCH during the OnDuration time in a next DRX cycle (or a configured number of next DRXcycles).

In some embodiments, such as for out-of-coverage UEs or Mode 2 UEs, thepower saving signal or channel can be independent from a Uu link powersaving signal or channel and can be provided by a SCI format in a PSCCHor by a PSSCH.

FIG. 26 illustrates a sidelink power saving signal or channel accordingto various embodiments of the present disclosure. More particularly,FIG. 26 illustrates an example of a sidelink power saving signal orchannel that wakes up a UE to monitor PSCCH in a subsequent On Durationtime of a next DRX cycle. The embodiment of the sidelink power savingsignal or channel shown in FIG. 26 is for illustration only. Otherembodiments can be used without departing from the scope of the presentdisclosure.

As shown in FIG. 26, when there is no data to transmit to the powersaving UE 116 in a next DRX cycle, the UE 118 can transmit a powersaving signal or channel to the power saving UE 116 so that the powersaving UE 116 does not wake up (does not monitor PSCCH) in the next DRXcycle.

In some embodiments, the configuration illustrated in FIG. 26 can beprovided by PC5 higher layers after a unicast connection is establishedamong UEs on the sidelink. The configuration for the sidelink powersaving signal or channel can include one or more of a monitoringperiodicity, a monitoring time offset relative to the start of a DRXcycle, and a monitoring pattern within a slot. The monitoring patterncan indicate at least one of time domain or frequency domain locationwithin a slot for power saving signal/channel monitoring. The monitoringperiodicity can also have values that are integer multiples of thelength of the DRX cycle.

In some embodiments, information fields of a SCI format used to providepower saving information can include dynamic DRX parameters, such as thelength of onDurationTimer, drx-InactivityTimer, and DRX cycle. Theinformation fields can further include an indication of a carrier wherethe UE switches from a dormant state to monitor PSCCH when the UE isconfigured for operation with carrier aggregation (or where the UEswitches to a dormant state if the UE was previously in an active statefor monitoring PSCCH). The information fields can further include anindication of a BWP where the UE monitors PSCCH when the UE isconfigured for operation with multiple BWPs or of a BWP where the UEdoes not monitor PSCCH. The information fields can further includeinformation related to decoding of PSCCH that provides a SCI format forPSSCH scheduling such as one or more of the staring symbol of the PSCCH,the number of symbols of the PSCCH, and the starting subchannel/RB andnumber of RBs that the PSCCH occupies, to dynamically control a numberof PSCCH decoding operations a UE needs to perform in the following DRXcycle.

In embodiments where the power saving signal or channel is provided byan SCI format or by a PSSCH, the information provided by the SCI formatcan be configured by higher layers.

In some embodiments, there can be multiple sidelink connections betweenthe UE 116 and other UEs 118. In these embodiments, the UE 116 can use asame set of DRX parameters for all sidelink connections with other UEsand the UEs can use a same resource for a transmission of a power savingsignal or channel if the power saving signal or channel from othervehicle UEs provides a same information, such as whether or not tomonitor PSCCH during the On Duration time in a next DRX cycle, withoutcarrying some transmitter UE specific information. If the power savingsignal or channel from other UEs does not provide same information, orif the transmissions from the other UEs in a same resource cannot becombined by the receiver UE 116, the UEs can use different resources fortransmission of their respective power saving signal or channel.

In some embodiments, a power saving signal or channel can be used toreduce power consumption for a group of UEs in a groupcast or broadcastmode. Since all UEs in a group are waken up to monitor PSCCHsimultaneously by a power saving signal or channel, the power savingsignal or channel configuration can be same for all UEs in the group.

In embodiments where a UE is an in-coverage Mode 1 UE, a power savingsignal or channel can have a same structure as a Uu link power savingsignal or channel. For example, a power saving signal or channel can bea DCI format in a PDCCH that is applicable to one or both of the Uu linkand the sidelink transmission/reception. Same DRX cycle parameters canbe configured for sidelink and Uu link. In embodiments where a UEoperates in a shared carrier for Uu link and sidelink and any one of thepower saving signal or channel indicates to the UE to wake up to monitorPSSCH in a next DRX cycle, the UE wakes up to monitor PSSCH in the nextDRX cycle. In embodiments where the UE operates in different carriersfor Uu link and sidelink, the UE wakes up to monitor PDCCH or PSSCH(when so indicated) in respective carriers indicated by the power savingsignal or channel.

FIG. 27 illustrates a Mode 1 power saving signal or channel for a PDCCHaccording to various embodiments of the present disclosure. Theembodiment of the Mode 1 power saving signal or channel shown in FIG. 27is for illustration only. Other embodiments can be used withoutdeparting from the scope of the present disclosure.

As shown in FIG. 27, a Uu link power saving signal or channel triggers aUE to monitor PSCCH in the sidelink. In the example illustrated in FIG.27, the sidelink and Uu link operate in different carriers.

FIG. 28 illustrates a method for indicating to a UE whether or not tomonitor PDCCH or PSSCH in next respective DRX cycles on the Uu link orthe sidelink through a DCI format in a PDCCH power saving signal orchannel in Mode 1 sidelink according to various embodiments of thepresent disclosure. Although described herein as being implemented bythe UE 116, the method 2800 illustrated in FIG. 28 can be implemented byone or more of the UEs 111-116 and a corresponding method can beperformed by one or more of the gNBs 101-103 described in FIG. 1. Otherembodiments can be used without departing from the scope of the presentdisclosure.

In operation 2810, a UE, such as the UE 116, receives a signal. Thesignal can be transmitted from a gNB, such as the gNB 102, or fromanother UE, such as the UE 118.

In operation 2820, the UE 116 determines whether a DCI format providingpower saving information in a PDCCH (PS-PDCCH) is detected as the signalreceived in operation 2810. If a DCI format in a PS-PDCCH is notdetected, the UE 116 proceeds to operation 2830 and determines to notwake up. If a DCI format in a PS-PDCCH is detected, the UE 116 proceedsto operation 2840.

In operation 2840, the UE 116 determines whether the DCI format in thePS-PDCCH indicates to the UE to wake up for sidelink only. If the UE 116determines the DCI format in the PS-PDCCH indicates to wake up forsidelink only, the UE 116 proceeds to operation 2850 and monitors thePSCCH in sidelink. If the UE 116 determines that the DCI format in thePS-PDCCH does not indicate to wake up for sidelink only, the UE 116proceeds to operation 2860 and determines whether the DCI format in thePS-PDCCH indicates to wake up for the Uu link only.

If the UE 116 determines, in operation 2860, that the DCI format in thePS-PDCCH indicates to wake up for the Uu link only, in operation 2870the UE 116 monitors PDCCH in the Uu link. If the 116 determines, inoperation 2860, that the DCI format in the PS-PDCCH does not indicate towake up for the Uu link only, in operation 2880 the UE 116 determinesthat the DCI format in the PS-PDCCH indicates to the UE 116 to wake upfor both the Uu link and the sidelink. Accordingly, the UE 116 monitorsboth the PDCCH in the Uu link and the PSCCH in the sidelink. If the DCIformat indicates to the UE to not wake up for either the Uu link or thesidelink, the UE does not monitor PDCCH or PSCCH, respectively, in nextcorresponding DRX cycles.

In another embodiment, a separate power saving signal or channel forsidelink can be used to trigger PSCCH monitoring in a next DRX cycle.For example, a SCI format in a PS-PSCCH can indicate to the UE 116whether or not to wake up. As another alternative, a combination of aSCI format in a PS-PSCCH and an information element in PS-PSSCH can bethe power saving channels. In addition to whether or not the UE 116needs to monitor PSCCH in a next DRC cycle, the power saving informationcan include an adaptation of parameters for PSSCH reception such as anumber of MIMO layers or a minimum time separation between a PSCCHreception and corresponding scheduled PSSCH. A configuration forreception of a power saving signal or channel at sidelink and aconfiguration for the associated information can be same forout-of-coverage UEs or Mode 2 UEs as for Mode 1 UEs.

In various embodiments, the DRX cycle parameters for sidelink and Uulink can be the same or different. The UE can wake up independently byrespective power saving signals or channels in Uu link and sidelink. Thestructure of the power saving signal or channel can also be different inthe Uu link and the sidelink. For example, a DCI format in a PS-PDCCHcan be used in the Uu link while a sequence through a signal can be usedin the sidelink.

In embodiments where a UE, such as the UE 116, operates in a sharedcarrier for Uu link and sidelink, a configuration for DRX cycleparameters can be common for sidelink and Uu link. It is also possiblethat a configuration for DRX cycle parameters is separately provided forthe Uu link and for the sidelink and the parameter values can be same ordifferent. When any one of the power saving signal or channel indicatesto the UE 116 to wake up in a next DRX cycle, the UE 116 wakes up innext DRX cycle for both Uu link to monitor PDCCH and sidelink to monitorPSSCH; otherwise, the UE does not wake up and does not monitor either ofPDCCH and PSCCH.

In embodiments where a UE, such as the UE 116, operates in differentcarriers for Uu link and sidelink, a configuration for DRX cycleparameters can be separate or common for sidelink and Uu link. The UE116 wakes up in the carrier indicated by respective power savingsignals/channels. The UE 116 can benefit by reduced power consumption oneither the Uu link or the sidelink from respective power savingsignals/channels that are mutually independent.

FIG. 29 illustrates a method of a Mode 1 power saving signal or channelfor PSCCH and PDCCH according to various embodiments of the presentdisclosure. The embodiment of the method shown in FIG. 29 is forillustration only. Other embodiments can be used without departing fromthe scope of the present disclosure.

In some embodiments, as shown in FIG. 29, a sidelink power saving signalor channel indicates whether or not the UE 116 monitors PSCCH in a nextDRX cycle in the sidelink and a Uu link power saving signal or channelindicates whether or not the UE 116 monitors PDCCH in a next DRX cyclein the Uu link where the sidelink and Uu link operate in differentcarriers and DRX cycle configurations are same or different for thesidelink and Uu link.

In other embodiments, a separate power saving signal or channel forsidelink and for Uu link can be used to indicate to the UE 116 whetheror not to monitor PSCCH in a next DRX cycle in the sidelink or PDCCH ina next DRX cycle in the Uu link. For example, the power saving signal orchannel for sidelink can be provided by a separate DCI format in a PDCCHthan the DCI format for Uu link. The separate power saving signals orchannels for sidelink and Uu link can be configured to be in a same orin a different BWP or carrier. DRX cycle parameters for sidelink and Uulink can be provided by a common configuration from higher layers or byseparate configurations from higher layers.

In embodiments where the UE 116 operates in a shared carrier for Uu linkand sidelink, DRX cycle parameters can be provided by a commonconfiguration by higher layers for sidelink and Uu link. When any one ofthe power saving signal or channel indicates to the UE 116 to wake up ina next DRX cycle, the UE 116 wakes up in the next DRX cycle for both Uulink to monitor PDCCH and sidelink to monitor PSCCH. If the indicationis for the UE to now wake up, the UE does not monitor PDCCH or PSCCH.

In embodiments where the UE 116 operates in different carriers for Uulink and sidelink, DRX cycle parameters can be provided by same orseparate configurations from higher layers for sidelink and Uu link. TheUE 116 wakes up in the carrier indicated by respective power savingsignals or channels. For example, a DCI format in a PDCCH or a DCIformat in another PDCCH can indicate to the UE 116 the carriers and/orcells to monitor PDCCH or the carriers to monitor PSCCH, respectively.Then, the UE 116 can benefit by reduced power consumption fromindependent power saving signals or channels.

FIG. 30 illustrates a use of separate Mode 1 power savings channels forsidelink and Uu link according to various embodiments of the presentdisclosure. The embodiment of the Mode 1 power saving signal or channelshown in FIG. 30 is for illustration only. Other embodiments can be usedwithout departing from the scope of the present disclosure.

As shown in FIG. 30, a first DCI format in a PDCCH indicates to the UE116 whether or not to monitor PSCCH in a next DRX cycle in the sidelinkand a second DCI format in a PDCCH indicates to the UE 116 whether ornot to monitor PDCCH in a next DRX cycle in the Uu link where thesidelink and the Uu link operate on different carriers while the UE canreceive the power saving channels on the same carrier.

In some embodiments, the configuration for an in-coverage sidelink powersaving signal or channel can be provided to the UE 116 by Uu higherlayers after the UE 116 establishes an RRC connection with the gNB. Forexample, the configuration can be provided to both the transmitter UE118 and to the power saving UE 116 in their respective Uu links.

FIG. 31 illustrates an RRC configuration for power saving signals orchannels according to various embodiments of the present disclosure. Theembodiment of the RRC configuration shown in FIG. 31 is for illustrationonly. Other embodiments can be used without departing from the scope ofthe present disclosure.

FIG. 31 illustrates a gNB 3110, a power saving UE 3120, and a non-powersaving UE 3130. The gNB 3110 can be the gNB 102. Both the power savingUE 3120 and the non-power saving UE 3130 can be one of the UEs 111-118.As shown in FIG. 31, the gNB 3110 provides a power saving configurationfor both the power saving UE 3120 and the non-power saving UE 3130.

In some embodiments, the configuration for a sidelink power savingsignal or channel is provided only to the power saving UE in the Uulink, while the configuration for sidelink power saving signal orchannel for the transmitter UE is provided in the sidelink by thereceiver UE after a PC5-RRC connection is established.

FIG. 32 illustrates an RRC and PC5-RRC configuration for a power savingsignal or channel according various embodiments of the presentdisclosure. The embodiment of the RRC and PC5-RRC configurations shownin FIG. 32 is for illustration only. Other embodiments can be usedwithout departing from the scope of the present disclosure.

FIG. 32 illustrates a gNB 3210, a power saving UE 3220, and a non-powersaving UE 3230. The gNB 3210 can be the gNB 102. Both the power savingUE 3220 and the non-power saving UE 3230 can be one of the UEs 111-118.The gNB 3210 provides a configuration for a power saving signal orchannel reception by a power saving UE 3220 and the power saving UE 3220provides a power saving configuration for the non-power saving UE 3230to transmit a power saving signal or channel.

In some embodiments, the configuration for a sidelink power savingsignal or channel to a Mode 1 UE can include whether the power savingchannel is a PDCCH or a PSCCH. When the power saving channel is a PDCCH,the configuration can also include corresponding PDCCH monitoringparameters when the PDCCH for sidelink power savings is not same as thePDCCH for Uu link power savings.

In some embodiments, the configuration for the Mode 1 PSCCH sidelinkpower saving signal or channel can include one or more of monitoringperiodicity, monitoring offset relative to the start of a next DRXcycle, or monitoring pattern within a slot. The monitoring pattern canindicate a time domain and/or a frequency domain location within a slotfor power saving signal monitoring. The monitoring periodicity can alsohave values that are integer multiples of the length of the DRX cycle.

In some embodiments, the configuration for monitoring a Mode 1 PDCCHsidelink power saving channel can be same as for monitoring a Uu PDCCHpower saving channel. The UE-specific configuration of search space setsfor a DCI format in a PDCCH can be used to enable UE power savings forthe UE to monitor outside Active Time. The CORESET(s) for the PDCCHreception outside Active Time can include at least one of the CORESET(s)configured for PDCCH monitoring inside Active Time.

In some embodiments, information fields of the DCI format in the PDCCHthat are used to enable the UE power savings can include a field (whenthe PDCCH provides a DCI format for power saving in both the sidelinkand the Uu link) that indicates PSCCH monitoring in sidelink only,PDCCH/PSCCH monitoring in both sidelink and Uu link, or PDCCH monitoringin Uu link only. For example, the field can have 2 bits wherein a firstbit indicates whether or not the UE monitors PDCCH in a next DRX cyclefor the Uu link and a second bit indicates whether or not the UEmonitors PSCCH in a next DRX cycle for the sidelink. When the UE isconfigured for carrier aggregation operation in the sidelink, a field inthe DCI format (when the sidelink power saving signal/channel is aPDCCH) or the SCI format (when the sidelink power saving signal orchannel is a PSCCH) that indicates the carrier or carriers where the UEwakes up to monitor PSCCH or where the UE does not wake up to monitorPSCCH. When the UE is configured for multiple BWPs operation in thesidelink, a field in the DCI format (when the sidelink power savingsignal or channel is a PDCCH) or SCI format (when the sidelink powersaving signal/channel is a PSCCH) can indicate the BWP where the UEmonitors PSCCH or the BWP where the UE remains in a dormant state anddoes not monitor PSCCH.

Information fields can further include dynamic DRX parameters, such asthe length of onDurationTimer, drx-InactivityTimer, and DRX cycle.Information fields can further include information related to thedecoding of a PSCCH that provides a SCI format for PSSCH scheduling,such as a starting symbol of the PSCCH reception, a number of symbols ofthe PSCCH, and a starting RB and a number of RBs for the PSCCHreception.

Various embodiments of the present disclosure provide support of a DRXoperation with a reservation signal. A reservation signal can be used toreserve resources for an initial transmission of a TB in a PSCCH. Thereservation signal can be a SCI format in a PSCCH that does not schedulea PSSCH transmission or be an SCI format in a PSCCH that schedules aPSSCH transmission. The reservation signal can be used as a sidelinkpower saving signal or channel to indicate to a UE whether or not tomonitor PSCCH in the subsequent On Duration time of next DRX cycle.

FIG. 33 illustrates a sidelink power saving signal or channel in a formof a reservation signal according to various embodiments of the presentdisclosure. The embodiment of the sidelink power saving signal orchannel shown in FIG. 33 is for illustration only. Other embodiments canbe used without departing from the scope of the present disclosure.

The sidelink power saving signal or channel in the form of thereservation signal illustrated in FIG. 33 can indicate to a UE, such asthe UE 116, whether or not to monitor PSCCH in the subsequent OnDuration time of a next DRX cycle. In embodiments where there is no datato transmit to the UE 116 in the next DRX cycle, a UE, such as the UE118, may not transmit a reservation signal so that UE 116 does not wakeup in next DRX cycle. A behavior of a UE when the UE does not detect areservation signal or a SCI format providing an indication for whetheror not the UE monitors PSCCH in a next DRX cycle can be configured tothe UE to be either that the UE monitors PSCCH or that the UE does notmonitor PSCCH in the next DRX cycle.

In some embodiments, the configuration for the sidelink power savingsignal or channel in a form of a reservation signal can be provided byhigher layers after a unicast connection is established among UEs. Aconfiguration for the sidelink power saving signal or channel as areservation signal can include one or more parameters includingmonitoring periodicity, monitoring offset relative to the start of anext DRX cycle, and monitoring pattern within a slot for reservationsignal. In some embodiments, the monitoring pattern can indicate a timedomain and/or a frequency domain location within a slot for power savingsignal or channel monitoring (reservation signal). The monitoringperiodicity can also be configured to have a same or different value asthe length of DRX cycle including an integer multiple of the length ofthe DRX cycle in a number of slots or in milliseconds.

In some embodiments, additional information fields of a reservationsignal for a power saving signal or channel can include DRX parameters,such as a length of onDurationTimer, drx-InactivityTimer, and DRX cycle.The additional information fields can further include, when the UE 116is configured for carrier aggregation operation in sidelink, a field inthe SCI format that indicates the carrier(s) where the UE 116 monitorsPSCCH and the carriers where the UE does not monitor PSCCH in respectiveDRX cycles. The additional information fields can further include, whenthe UE 116 is configured for operation in one BWP from multiple BWPs insidelink, a field in the SCI format that indicates a BWP where the UE116 monitors PSCCH or a BWP where the UE does not monitor PSCCH. Theadditional information fields can further include information related todecoding of PSCCH that provides a SCI format for PSSCH scheduling, suchas a starting symbol of the PSCCH, a number of symbols of the PSCCH, anda starting subchannel/RB and a number of RBs for the PSCCH reception.

In embodiments where a reservation signal for power saving signal orchannel is in a form of a SCI format in a PSCCH, the information thatthe SCI format provides can be configured to the UE 116 by higherlayers. In embodiments where the reservation signal for power savingsignal or channel is in a form of a SCI format in a PSCCH that schedulesa PSSCH, the information provided by the SCI format and the by the PSSCHpayload can be configured to the UE 116 by higher layers.

In embodiments where there are multiple sidelink connections between aUE and other UEs, the UE, such as the UE 116, can be provided a same setof DRX cycle parameters for all the sidelink connections with the otherUEs, such as the UE 118. In these embodiments, the power saving signalor channel from different UEs 118 can use different reservation signalresources for transmission. If the UE 116 operates in a Mode 2, theconfiguration for reservation signal can be provided to other UEs 118 insidelink by the UE 116.

In some embodiments, a group of UEs can be in a groupcast or broadcastmode. In these embodiments, a reservation signal can be used as a powersaving signal or channel to reduce power consumption for the group ofUEs. Since all UEs in the group need to be indicated by the reservationsignal to either monitor or not monitor PSCCH, a same reservation signalconfiguration can be provided for all UEs in the group, such as for amonitoring periodicity, a monitoring offset relative to the start of anext DRX cycle, and a monitoring pattern within a slot. For Mode 2 UEsin the group, the configuration for a reservation signal can be providedto UEs in the group in sidelink by a UE in the group.

In embodiments where UEs are in in-coverage Mode 1, a configuration forreservation signal can be provided to a power saving UE by Uu higherlayers after the UE establishes RRC connection with a gNB. For example,the configuration can be provided to both a transmitter UE and a powersaving UE in their respective Uu links. As another example, theconfiguration is provided only to the power saving UE in the Uu linkwhile the configuration for the transmitter UE is provided in thesidelink by the power saving UE after PC5-RRC is established. In variousembodiments, this configuration procedure can also be applied to UEs ina groupcast or broadcast.

Various embodiments of the present disclosure provide resourceallocation for UEs. Partial resource sensing can be used for a UE, suchas a pedestrian UE, to reduce power consumption when the UE only sensesa partial set of the slots in the sensing window when the UE has data totransmit. When a DRX procedure is introduced in sidelink, the partialset of slots are selected from the slots that are configured to beactive in each DRX cycle within the sensing window.

In some embodiments, a UE, such as the UE 116, can determine to decide aresource selection/reselection in slot m. In these embodiments, the UE116 selects the possible candidate resources, such as Y slots, in a timeinterval [m+T1, m+T2]. The minimum allowed value of Y can be configuredor preconfigured to the UE 116. A selection of Y slots satisfies theconstraint that the selected slots fall within the active slots, such asslots in drx-onDurationTimer, in a next DRX cycle. Different UEs can beconfigured with different drx-StartOffset values so that respectivepossible Y candidate resources do not entirely overlap, and the resourceconflict probability can be reduced.

For any candidate resource in slot n within the set of Y slots, the UE116 senses at least slot n-P*k that falls within the active slots, suchas slots in drx-onDurationTimer, in each DRX cycle in the sensing windowto detect whether or not the candidate resource in slot n is reserved byother UEs, where k is configured or pre-configured in a range between[k1, k2], and P is the period of the sensing slots.

FIG. 34 illustrates partial resource sensing and resource selection orreselection according to various embodiments of the present disclosure.The embodiment of the partial resource sensing and resource selection orreselection shown in FIG. 34 is for illustration only. Other embodimentscan be used without departing from the scope of the present disclosure.

As shown in FIG. 34, sensing slots can be located in each On Durationperiod in each DRX cycle. Candidate resources can also be located in theOn Duration period in a next DRX cycle. Candidate resources in theselection window can be excluded by a UE if the UE detects a SCI formatin the sensing slots of the sensing window that indicates that theresource is reserved by another UE. In embodiments where a power savingsignal or channel is considered in the DRX procedure and the UE does notmonitor PSCCH in a DRX cycle if a power saving signal or channel is notreceived, the UE can skip the sensing slot in the DRX cycle.

FIG. 35 illustrates partial resource sensing and resource selection orreselection with a power saving signal or channel according to variousembodiments of the present disclosure. The embodiment of the partialresource sensing and resource selection or reselection shown in FIG. 35is for illustration only. Other embodiments can be used withoutdeparting from the scope of the present disclosure.

As shown in FIG. 35, partial resource sensing and resource selection canbe performed when a UE, such as the UE 116, monitors a power savingsignal or channel before each DRX cycle. Sensing slots can be located ineach On Duration period in each DRX cycle. Candidate resources can belocated in the On Duration period in a next DRX cycle. In one DRX cycle,a power saving signal/channel indicates to the UE 116 to monitor PSCCHin the On Duration period. The UE 116 can use for resource sensing slotsin a respective DRX cycle. In another DRX cycle, a power saving signalor channel indicates to the UE 116 to not monitor PSCCH in an OnDuration period and the UE 116 does not use slots in this DRX cycle forresource sensing. The UE 116 can exclude a candidate resource in aselection or reselection window when a detected SCI format in thesensing slots of the sensing window indicates that the resource isreserved by another UE.

In some embodiments, the UE 116 can skip sensing slots in a DRX cyclewhen a power saving signal or channel is provided by a DCI format in aPDCCH for Mode 1 operation and the UE 116 does not monitor PSCCH in aDRX cycle when the UE 116 does not detect the DCI format or when the UE116 detects the DCI format and the indication is to skip PSCCHmonitoring.

In various embodiments, a UE can perform RSSI measurements in slotsn-P*k that are within the active slots, such as a drx-onDurationTimer,in each DRX cycle in the sensing window. The UE selects one of thecandidate resources with the lowest value for the RSSI measurements inthe resource selection or reselection window. A RSSI value for eachcandidate resource in the resource selection or reselection window is alinear average of a RSSI measurement on all subchannels that areoccupied by the candidate resource and slots n-P*k that are within theactive slots, such as the drx-onDurationTimer, in each DRX cycle in thesensing window. Similar, k can be configured or pre-configured in arange between [k1, k2], wherein P is a period of the sensing slots.

FIG. 36 illustrates a method of providing HARQ-ACK information accordingto various embodiments of the present disclosure. Although describedherein as being implemented by the UE 116, the method 3600 illustratedin FIG. 36 can be implemented by one or more of the UEs 111-116described in FIG. 1. Other embodiments can be used without departingfrom the scope of the present disclosure.

In operation 3610, a UE, such as the UE 116, receives a configurationfor a slot offset value. In operation 3620, the UE 116 receives a PSSCHover a number of sub-channels in a first slot. The PSSCH includes a TB.

In operation 3630, the UE 116 determines a second slot as an earliestslot with resources for transmission of a PSFCH that is after the firstslot by a number of slots equal to the slot offset value. The PSFCH caninclude the HARQ-ACK information that is in response to reception of theTB. In operation 3640, the UE 116 transmits the PSFCH in the secondslot.

In some embodiments, the method 3600 further includes receiving aconfiguration for a number of slots. The resources for the PSFCHtransmission can exist with a periodicity equal to the number of slots.When HARQ-ACK information reporting is enabled for groupcasttransmissions, the HARQ-ACK information in the PSFCH transmission caninclude (i) only NACK value(s) or (ii) either ACK or NACK value(s).

In some embodiments, sub-channels and slots are mapped to the resourcesfor the PSFCH transmission first in ascending order of a slot index,starting from a first sub-channel index, and then in ascending order ofa sub-channel index, starting from a first slot index.

In some embodiments, the method 3600 further includes determining anumber of resources for the PSFCH transmission in a slot for the PSFCHtransmission. In some embodiments, the method 3600 further comprisesdetermining to use the slot as the second slot for the PSFCHtransmission based on determining that the number of resources is largerthan or equal to a value.

In some embodiments, the method 3600 further includes receiving a firstSCI format that includes an indication of time resources and offrequency resources for a PSSCH reception, receiving a second SCI formatthat includes an identity of a zone, determining an indication whetherto transmit the PSFCH based on the identity of the zone, andtransmitting the PSFCH based on the indication.

FIG. 37 illustrates a method of obtaining HARQ-ACK information accordingto various embodiments of the present disclosure. Although describedherein as being implemented by the UE 116, the method 3700 illustratedin FIG. 37 can be implemented by one or more of the UEs 111-116described in FIG. 1. Other embodiments can be used without departingfrom the scope of the present disclosure.

In operation 3710, a UE, such as the UE 116, transmits a configurationfor a slot offset value. In operation 3720, the UE 116 transmits a PSSCHover a number of sub-channels in a first slot. The PSSCH includes a TB.

In operation 3730, the UE 116 determines a second slot as an earliestslot with resources for the reception of a PSFCH that is after the firstslot by a number of slots equal to the slot offset value.

In operation 3740, the UE 116 receives the PSFCH in the second slot. Insome embodiments, the PSFCH can include the HARQ-ACK information that isin response to the transmission of the TB.

In some embodiments, the method 3700 further includes transmitting aconfiguration for a number of slots. The resources for the PSFCHreception can exist with a periodicity equal to the number of slots.When HARQ-ACK information reporting is enabled for groupcasttransmissions, the HARQ-ACK information in the PSFCH reception caninclude (i) only NACK value(s) or (ii) either ACK or NACK value(s).

In some embodiments, sub-channels and slots can be mapped to theresources for the PSFCH reception first in ascending order of a slotindex, starting from a first sub-channel index, and then in ascendingorder of a sub-channel index, starting from a first slot index.

In some embodiments, the method 3700 further includes determining anumber of resources for the PSFCH reception in a slot for the PSFCHreception and determining the slot as the second slot for the PSFCHreception based on determining that the number of resources is largerthan or equal to a value.

In some embodiments, the method 3700 further includes transmitting afirst SCI format that includes an indication of time resources andfrequency resources for the PSSCH transmission, transmitting a secondSCI format that includes an identity of a zone, determining anindication whether to receive the PSFCH based on the identity of thezone, and receiving the PSFCH based on the indication.

The above flowcharts illustrate examples of methods that can beimplemented in accordance with the principles of the present disclosureand various changes could be made to the methods illustrated in theflowcharts. For example, while shown as a series of steps, various stepsin each figure could overlap, occur in parallel, occur in a differentorder, or occur multiple times. In another example, steps may be omittedor replaced by other steps.

Although the present disclosure has been described with an exampleembodiment, various changes and modifications can be suggested by or toone skilled in the art. It is intended that the present disclosureencompass such changes and modifications as fall within the scope of theappended claims.

What is claimed is:
 1. A method for a user equipment (UE) to provide hybrid automatic repeat request acknowledgement (HARQ-ACK) information, the method comprising: receiving a configuration for a slot offset value; receiving a physical sidelink shared channel (PSSCH) over a number of sub-channels in a first slot, wherein the PSSCH includes a transport block (TB); determining a second slot as an earliest slot with resources for transmission of a physical sidelink feedback channel (PSFCH) that is after the first slot by a number of slots equal to the slot offset value, wherein the PSFCH includes the HARQ-ACK information that is in response to reception of the TB; and transmitting the PSFCH in the second slot, wherein sub-channels and slots of PSSCH receptions are mapped to resources for corresponding PSFCH transmissions first in ascending order of a slot index, starting from a first sub-channel index, and then in ascending order of a sub-channel index, starting from a first slot index.
 2. The method of claim 1, further comprising: receiving a configuration for a number of slots, wherein the resources for the transmission of the PSFCH exist with a periodicity equal to the number of slots.
 3. The method of claim 1, further comprising: determining a number of resources for the transmission of the PSFCH in the second slot; and transmitting the PSFCH in the second slot based on determining that the number of resources is larger than or equal to a value.
 4. The method of claim 1, further comprising: receiving a first sidelink control information (SCI) format that includes an indication of time resources and frequency resources for the reception of the PSSCH; receiving a second SCI format that includes an identity of a zone; determining an indication whether to transmit the PSFCH based on the identity of the zone; and transmitting the PSFCH based on the indication.
 5. A user equipment (UE) comprising: a transceiver configured to: receive a configuration for a slot offset value, and receive a physical sidelink shared channel (PSSCH) over a number of sub-channels in a first slot, wherein the PSSCH includes a transport block (TB); a processor operably connected to the transceiver, the processor configured to determine a second slot as an earliest slot with resources for transmission of a physical sidelink feedback channel (PSFCH) that is after the first slot by a number of slots equal to the slot offset value, wherein the PSFCH includes hybrid automatic repeat request acknowledgement (HARQ-ACK) information in response to reception of the TB; and wherein the transceiver is further configured to transmit the PSFCH in the second slot, and wherein sub-channels and slots of PSSCH receptions are mapped to resources for corresponding PSFCH transmissions first in ascending order of a slot index, starting from a first sub-channel index, and then in ascending order of a sub-channel index, starting from a first slot index.
 6. The UE of claim 5, wherein: the transceiver is further configured to receive a configuration for a number of slots, and the resources for the transmission of the PSFCH exist with a periodicity equal to the number of slots.
 7. The UE of claim 5, wherein: the processor is further configured to determine a number of resources for the transmission of the PSFCH in the second slot; and the transceiver is further configured to transmit the PSFCH in the second slot based on determining that the number of resources is larger than or equal to a value.
 8. The UE of claim 5, wherein: the transceiver is further configured to: receive a first sidelink control information (SCI) format that includes an indication of time resources and of frequency resources for the reception of the PSSCH, and receive a second SCI format that includes an identity of a zone; the processor is further configured to determine an indication whether to transmit the PSFCH based on the identity of the zone; and the transceiver is further configured to transmit the PSFCH based on the indication.
 9. A method for a user equipment (UE) to obtain hybrid automatic repeat request acknowledgement (HARQ-ACK) information, the method comprising: transmitting a configuration for a slot offset value; transmitting a physical sidelink shared channel (PSSCH) over a number of sub-channels in a first slot, wherein the PSSCH includes a transport block (TB); determining a second slot as an earliest slot with resources for reception of a physical sidelink feedback channel (PSFCH) that is after the first slot by a number of slots equal to the slot offset value; and receiving the PSFCH in the second slot, wherein the PSFCH includes the HARQ-ACK information that is in response to transmission of the TB, and wherein sub-channels and slots for PSSCH transmissions are mapped to resources for corresponding PSFCH receptions first in ascending order of a slot index, starting from a first sub-channel index, and then in ascending order of a sub-channel index, starting from a first slot index.
 10. The method of claim 9, further comprising: transmitting a configuration for a number of slots, wherein the resources for the reception of the PSFCH exist with a periodicity equal to the number of slots.
 11. The method of claim 9, further comprising: determining a number of resources for the reception of the PSFCH in the second slot for the reception of the PSFCH; and receiving the PSFCH in the second slot based on determining that the number of resources is larger than or equal to a value.
 12. The method of claim 9, further comprising: transmitting a first sidelink control information (SCI) format that includes an indication of time resources and frequency resources for the transmission of the PSSCH; transmitting a second SCI format that includes an identity of a zone; determining an indication whether to receive the PSFCH based on the identity of the zone; and receiving the PSFCH based on the indication.
 13. A user equipment (UE) comprising: a transceiver configured to: transmit a configuration for a slot offset value, and transmit a physical sidelink shared channel (PSSCH) over a number of sub-channels in a first slot, wherein the PSSCH includes a transport block (TB); a processor operably connected to the transceiver, the processor configured to determine a second slot as an earliest slot with resources for reception of a physical sidelink feedback channel (PSFCH) that is after the first slot by a number of slots equal to the slot offset value; and wherein the transceiver is further configured to receive the PSFCH in the second slot, wherein the PSFCH includes hybrid automatic repeat request acknowledgement (HARQ-ACK) information in response to transmission of the TB, and wherein sub-channels and slots for PSSCH transmissions are mapped to resources for corresponding PSFCH receptions first in ascending order of a slot index, starting from a first sub-channel index, and then in ascending order of a sub-channel index, starting from a first slot index.
 14. The UE of claim 13, wherein: the transceiver is further configured to transmit a configuration for a number of slots, and the resources for the reception of the PSFCH exist with a periodicity equal to the number of slots.
 15. The UE of claim 13, wherein: the processor is further configured to determine a number of resources for the reception of the PSFCH in the second slot for the reception of the PSFCH; and the transceiver is further configured to receive the PSFCH in the second slot based on determining that the number of resources is larger than or equal to a value.
 16. The UE of claim 13, wherein: the transceiver is further configured to: transmit a first sidelink control information (SCI) format that includes an indication of time resources and of frequency resources for the transmission of the PSSCH, and transmit a second SCI format that includes an identity of a zone; the processor is further configured to determine an indication whether to receive the PSFCH based on the identity of the zone; and the transceiver is further configured to receive the PSFCH based on the indication. 